drm/amd/display: Remove redundant condition in VBA 314 func

[WHY]
Coverity analysis this conditional code as DEADCODE.
The conditional statement is never true since
'MacroTileSizeBytes' is either 256 or 65536. Thus, the
code inside is the conditional statement is never reached.

[HOW]
Removed the conditional statement.

Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Ivan Lipski <ivlipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>