drm/i915: Move intel_guc_wopcm_size to intel_guc.c

drm/i915: Move intel_guc_wopcm_size to intel_guc.c

Function intel_guc_wopcm_size didn't fit well in the old place.
With this move upcoming cleanup will be simpler.

Suggested-by: Joonas Lahtinen <[email protected]>
Signed-off-by: Michal Wajdeczko <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Sagar Arun Kamble <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
Signed-off-by: Joonas Lahtinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]