drm/amd/display: To change dcn301_init.h guard.

[why & How]
The original guard is wrongly to be set as for dcn30.
Changed it from 30 to 301.

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Bhuvanachandra Pinninti <bpinnint@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>