drm/amdgpu: Verify bo size can fit framebuffer size on init.

To initialize the framebuffer, call drm_gem_fb_init_with_funcs which
verifies that the BO size can fit the FB size by calculating the minimum
expected size of each plane.

The bug was caught using igt-gpu-tools test: kms_addfb_basic.too-high
and kms_addfb_basic.bo-too-small

Tested on ChromeOS Zork by turning on the display and running a YT
video.

=== Changes from v1 ===
1. Added new line under declarations.
2. Use C style comment.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Mark Yacoub <markyacoub@chromium.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>