Merge ~jawn-smith/curtin:master into curtin:master

[William Wilson]

Add riscv64 to supported UEFI architectures

As we prepare a RISC-V installer image, we need to add 'riscv64' to the
supported UEFI architectures. This commit does so by setting values
for grub_name and grub_target.

[William Wilson (jawn-smith)]

Dan, when you review this can you confirm the value for grub_target is correct? I was less sure about grub_target than grub_name.

[Dan Bungert (dbungert)]

review: Approve

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:699d09ca45031cbc34c027319a07788f6a67696e
https://jenkins.ubuntu.com/server/job/curtin-ci/278/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-amd64/278/
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-arm64/278/
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-ppc64el/278/
    SUCCESS: https://jenkins.ubuntu.com/server/job/curtin-ci/nodes=metal-s390x/278/

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/curtin-ci/278//rebuild

review: Approve (continuous-integration)

[Server Team CI bot (server-team-bot)]

Commit message lints:
- Line #2 has 96 too many characters. Line starts with: "As we prepare a RISC-V"...

review: Needs Fixing

[Server Team CI bot (server-team-bot)]

review: Approve (continuous-integration)

diff --git a/curtin/commands/install_grub.py b/curtin/commands/install_grub.py
index ba46bd2..74ffdf1 100644
--- a/curtin/commands/install_grub.py
+++ b/curtin/commands/install_grub.py
@@ -62,6 +62,9 @@ def get_grub_package_name(target_arch, uefi, rhel_ver=None):
         elif target_arch == 'i386':
             grub_name = 'grub-efi-ia32'
             grub_target = 'i386-efi'
+        elif target_arch == 'riscv64':
+            grub_name = 'grub-efi-riscv64'
+            grub_target = 'riscv64-efi'
         else:
             raise ValueError('Unsupported UEFI arch: %s' % target_arch)
     else: