drm/amdgpu: update psp_get_fw_type() function

drm/amdgpu: update psp_get_fw_type() function

In psp 15.0.8, mes and sdma GFX_FW_TYPE have been changed.

Define a psp common function: psp_get_fw_type().
Hide the GFX_FW_TYPE Changes in each ip's psp->funcs_get_fw_type callback.
(like psp_v15_0_8_get_fw_type()).
If no GFX_FW_TYPE change, reuse the amdgpu_psp_get_fw_type().

Signed-off-by: Feifei Xu <Feifei.Xu@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>