Code review comment for ~robertliu/+git/kernel-snap:uc22-add-custom-firmware

Thanks Ondrej,
I updated the snapcraft.yaml and built a version locally. However, the size is much bigger than the previous recipe (199MB vs 167MB). It seems that "trim-firmware" keeps most of linux-firmware.

$ ls prime/firmware/
3com cpia2 ipw2200-bss.fw iwlwifi-Qu-b0-hr-b0-66.ucode mts_gsm.fw regulatory.db.p7s usbduxsigma_firmware.bin
RTL8192E ct2fw-3.2.5.1.bin ipw2200-ibss.fw iwlwifi-Qu-b0-jf-b0-66.ucode mts_mt9234mu.fw rockchip v4l-cx231xx-avcore-01.fw
acenic ctefx.bin ipw2200-sniffer.fw iwlwifi-Qu-c0-hr-b0-66.ucode mts_mt9234zba.fw rp2.fw v4l-cx23418-apu.fw
adaptec ctfw-3.2.5.1.bin iwlwifi-100-5.ucode iwlwifi-QuZ-a0-hr-b0-66.ucode mwl8k rt2561.bin v4l-cx23418-cpu.fw
advansys cxgb3 iwlwifi-1000-5.ucode iwlwifi-QuZ-a0-jf-b0-66.ucode myri10ge_eth_z8e.dat rt2561s.bin v4l-cx23418-dig.fw
agere_ap_fw.bin cxgb4 iwlwifi-105-6.ucode iwlwifi-cc-a0-66.ucode myri10ge_ethp_z8e.dat rt2661.bin v4l-cx2341x-dec.fw
agere_sta_fw.bin dvb-fe-xc4000-1.4.1.fw iwlwifi-135-6.ucode iwlwifi-ty-a0-gf-a0-66.ucode myri10ge_rss_eth_z8e.dat rt2860.bin v4l-cx2341x-enc.fw
amdgpu dvb-fe-xc5000-1.6.114.fw iwlwifi-2000-6.ucode kaweth myri10ge_rss_ethp_z8e.dat rt2870.bin v4l-cx2341x-init.mpg
ar5523.bin dvb-fe-xc5000c-4.1.30.7.fw iwlwifi-2030-6.ucode keyspan netronome rt73.bin v4l-cx23885-avcore-01.fw
ath10k dvb-usb-dib0700-1.20.fw iwlwifi-3160-17.ucode keyspan_pda nvidia rtl_bt v4l-cx25840.fw
ath11k dvb-usb-it9135-01.fw iwlwifi-3168-29.ucode korg phanfw.bin rtl_nic v4l-pvrusb2-24xxx-01.fw
ath3k-1.fw dvb-usb-it9135-02.fw iwlwifi-3945-2.ucode lbtf_usb.bin qcom rtlwifi v4l-pvrusb2-29xxx-01.fw
ath6k e100 iwlwifi-4965-2.ucode lgs8g75.fw qed rtw88 vicam
ath9k_htc ea iwlwifi-5000-5.ucode libertas ql2100_fw.bin rtw89 vntwusb.fw
atmel edgeport iwlwifi-5150-2.ucode liquidio ql2200_fw.bin slicoss vxge
atmel_at76c504_2958.bin emi26 iwlwifi-6000g2a-6.ucode mediatek ql2300_fw.bin sun whiteheat.fw
atmel_at76c504a_2958.bin emi62 iwlwifi-6000g2b-6.ucode mellanox ql2322_fw.bin tehuti whiteheat_loader.fw
av7110 ene-ub6250 iwlwifi-6050-5.ucode microchip ql2400_fw.bin ti-connectivity wil6210.brd
bnx2 ess iwlwifi-7260-17.ucode moxa ql2500_fw.bin ti_3410.fw wil6210.fw
bnx2x f2255usb.bin iwlwifi-7265-17.ucode mrvl qlogic ti_5052.fw yam
brcm go7007 iwlwifi-7265D-29.ucode mt7601u.bin r8a779x_usb3_v1.dlmem tigon yamaha
cadence intel iwlwifi-8000C-36.ucode mt7662.bin r8a779x_usb3_v2.dlmem ttusb-budget zd1201-ap.fw
carl9170-1.fw ipw2100-1.3-i.fw iwlwifi-8265-36.ucode mt7662_rom_patch.bin r8a779x_usb3_v3.dlmem ueagle-atm zd1201.fw
cavium ipw2100-1.3-p.fw iwlwifi-9000-pu-b0-jf-b0-46.ucode mts_cdma.fw radeon usbdux_firmware.bin zd1211
cbfw-3.2.5.1.bin ipw2100-1.3.fw iwlwifi-9260-th-b0-jf-b0-46.ucode mts_edge.fw regulatory.db usbduxfast_firmware.bin