CVE-2024-47661

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

drm/amd/display: Avoid overflow from uint32_t to uint8_t

[WHAT & HOW]
dmub_rb_cmd's ramping_boundary has size of uint8_t and it is assigned
0xFFFF. Fix it by changing it to uint8_t with value of 0xFF.

This fixes 2 INTEGER_OVERFLOW issues reported by Coverity.