drm/amdgpu: check alignment on CPU page for bo map

The page table of AMDGPU requires an alignment to CPU page so we should
check ioctl parameters for it.  Return -EINVAL if some parameter is
unaligned to CPU page, instead of corrupt the page table sliently.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Xi Ruoyao <xry111@mengyan1223.wang>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org