CVE-2024-26729 drm/amd/display: Fix potential null pointer dereference in dc_dmub_srv

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix potential null pointer dereference in dcdmubsrv Fixes potential null pointer dereference warnings in the dcdmubsrvcmdlistqueueexecute and dcdmubsrvishwpwrup functions. In both functions, the 'dcdmubsrv'...