Comment 2 for bug 1830435

Verification:
(initramfs) cd /sys/class/sas_phy/phy-0\:0\:20
(initramfs)
(initramfs) cat negotiated_linkrate
12.0 Gbit
(initramfs) echo 0 > enable
[ 42.507684] hisi_sas_v3_hw 0000:74:02.0: phydown: phy0 phy_state=0xfe
[ 42.558239] hisi_sas_v3_hw 0000:74:02.0: erroneous completion iptt=4048 task=(____ptrval____) dev id=1 CQ hdr: 0x1103 0x10fd0 0x0 0x20000 Error info: 0x0 0x4000000 0x0 0x0
[ 42.573527] sas: smp_execute_task_sg: task to dev 500e004aaaaaaa1f response: 0x0 status 0x2
(initramfs) [ 42.583264] sas: ex 500e004aaaaaaa1f phy20 change count has changed

(initramfs) echo 0 > enable
(initramfs) cat negotiated_linkrate
Phy disabled