drm/amd/display: Fix 64-bit state pointer passed as 32-bit GPINT response buffer

drm/amd/display: Fix 64-bit state pointer passed as 32-bit GPINT response buffer

edp_pr_get_state() incorrectly casts a uint64_t * to uint32_t * when
calling dc_wake_and_execute_gpint(). The GPINT path writes only 32 bits,
leaving the upper 32 bits of the u64 output uninitialized. Replace the
cast with a u32 temporary and copy the result into the u64 pointer.

Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c
    1448 bool edp_pr_get_state(const struct dc_link *link, uint64_t *state)
                                                           ^^^^^^^^^^^^^^^
    1449 {

    ...

    1457         do {
    1458                 // Send gpint command and wait for ack
--> 1459                 if (!dc_wake_and_execute_gpint(dc->ctx, DMUB_GPINT__GET_REPLAY_STATE, panel_inst,
    1460                                                (uint32_t *)state, DM_DMUB_WAIT_TYPE_WAIT_WITH_REPLY)) {
                                                        ^^^^^^^^^^^^^^^^^

The dc_wake_and_execute_gpint() function doesn't take a u64, it takes a
u32.  It tries to initialize the state to zero at the start but that's
not going to work because of the type mismatch.  It suggests that
callers are allowed to pass uninitialized data to edp_pr_get_state() but
at present there are no callers so this is only a bug in the code but
doesn't affect runtime.

    1461                         // Return invalid state when GPINT times out
    1462                         *state = PR_STATE_INVALID;
    1463                 }

Fixes: 74ce00932e7e ("drm/amd/display: Refactor panel replay set dmub cmd flow")
Reported by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Robin Chen <robin.chen@amd.com>
Cc: Jack Chang <jack.chang@amd.com>
Cc: Leon Huang <Leon.Huang1@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>