drm/amdgpu: Add vbios info ioctl interface

Add AMDGPU_INFO_VBIOS_INFO subquery id for detailed vbios info.

Provides a way for the user application to get the VBIOS
information without having to parse the binary.
It is useful for the user to be able to display in a simple way the VBIOS
version in their system if they happen to encounter an issue.

V2:
Use numeric serial.
Parse and expose vbios version string.

V3:
Remove redundant data in drm_amdgpu_info_vbios struct.

V4:
64 bit alignment in drm_amdgpu_info_vbios.

v5: squash together all the reverts, etc. (Alex)

Signed-off-by: Jiawei Gu <Jiawei.Gu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>