Since `BiosImageType` is `repr(u8)`, if can safely be converted into a
`u8` but this is not obvious when doing this in the code.

Instead, implement `From<BiosImageType>` for `u8` so the cast can be
done in a single place, with a justifying comment.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/vbios.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index dbe0d6e4a015..a521c0a4df0f 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -50,6 +50,13 @@ fn try_from(code: u8) -> Result<Self> {
     }
 }
 
+impl From<BiosImageType> for u8 {
+    fn from(value: BiosImageType) -> Self {
+        // `BiosImageType` is `repr(u8)` and thus convertible without loss.
+        value as u8
+    }
+}
+
 // PMU lookup table entry types. Used to locate PMU table entries
 // in the Fwsec image, corresponding to falcon ucodes.
 #[expect(dead_code)]
@@ -711,7 +718,7 @@ fn image_type(&self) -> Result<BiosImageType> {
     fn is_last(&self) -> bool {
         // For NBSI images (type == 0x70), return true as they're
         // considered the last image
-        if self.pcir.code_type == BiosImageType::Nbsi as u8 {
+        if self.pcir.code_type == BiosImageType::Nbsi.into() {
             return true;
         }
 

-- 
2.51.0