drm/amd/display: Create FPU files for DCN314

DCN314 has multiple references to FPU operations inside the resource
files, and we need to move those codes to the DML folder. This commit
creates the dcn314_fpu files and moves the bounding box operation to
this file.

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>