drm/amd/display: Clamp HDMI HDCP2 rx_id_list read to buffer size

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

drm/amd/display: Clamp HDMI HDCP2 rx_id_list read to buffer size

[Why & How]

During HDCP 2.x repeater authentication over HDMI, the driver reads the

sink's RxStatus register and extracts a 10-bit message size field (max

value 1023). This value is used as the read length for the ReceiverID

list without being clamped to the size of the destination buffer

rx_id_list[177]. A malicious HDMI repeater could advertise a message

size larger than the buffer, causing an out-of-bounds write during the

I2C read.

Clamp the read length in mod_hdcp_read_rx_id_list() to the size of the

rx_id_list buffer, matching the approach already used in the DP branch.

(cherry picked from commit 229212219e4247d9486f8ba41ef087358490be09)