drm/amdgpu: Fix pointer casts when reading dynamic region sizes

drm/amdgpu: Fix pointer casts when reading dynamic region sizes

The function amdgpu_virt_get_dynamic_data_info() writes a 64-bit size
value.  In two places (amdgpu_bios.c and amdgpu_discovery.c), the code
passed the address of a smaller variable by casting it to u64 *, which
is unsafe.

This could make the function write more bytes than the smaller variable
can hold, possibly overwriting nearby memory. Reported by static
analysis tools.

v2: Dynamic region size comes from the host (SR-IOV setup) and is always
fixed to 5 MB. (Lijo/Ellen)

5 MB easily fits inside a 32-bit value, so using a 64-bit type is not
needed. It also avoids extra type casts

Fixes: b4a8fcc7826a ("drm/amdgpu: Add logic for VF ipd and VF bios to init from dynamic crit_region offsets")
Reported by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Ellen Pan <yunru.pan@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>