Ubuntu: (Multiple Advisories) (CVE-2024-49908): Linux kernel (OEM) vulnerabilities

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Add null check for 'afb' in amdgpu_dm_update_cursor (v2)

This commit adds a null check for the 'afb' variable in the
amdgpu_dm_update_cursor function. Previously, 'afb' was assumed to be
null at line 8388, but was used later in the code without a null check.
This could potentially lead to a null pointer dereference.

Changes since v1:
- Moved the null check for 'afb' to the line where 'afb' is used. (Alex)

Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:8433 amdgpu_dm_update_cursor()
error: we previously assumed 'afb' could be null (see line 8388)