drm/amd/display: increase max EDID size to 2k

[Why]
EDID CTS requires at least 2k (16 blocks) to be readable.

[How]
Increase EDID buffer size to 2k

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>