gpu: nova-core: vbios: use from_le_bytes() for PCI ROM header parsing

gpu: nova-core: vbios: use from_le_bytes() for PCI ROM header parsing

Clippy fires two clippy::precedence warnings on the manual
byte-shifting expression:
  warning: operator precedence can trip the unwary
     --> drivers/gpu/nova-core/vbios.rs:511:17
      |
  511 | /                 u32::from(data[29]) << 24
  512 | |                     | u32::from(data[28]) << 16
  513 | |                     | u32::from(data[27]) << 8
      | |______________________________________________^

Clear the warnings by replacing manual byte-shifting with
u32::from_le_bytes(). Using from_le_bytes() is also a tiny code
improvement, because it uses less code and is clearer about the intent.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Link: https://patch.msgid.link/20260404212831.78971-2-jhubbard@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>