drm/i915: Move FBC stuff to intel_fbc.c

No functional changes. This is just the begin of a FBC rework.

v2 (Paulo):
  - Revert intel_fbc_init() changed parameter.
  - Revert set_no_fbc_reason() rename.
  - Rebase.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index e4083e4..3cf70a6 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -47,6 +47,7 @@
 i915-y += intel_audio.o \
 	  intel_bios.o \
 	  intel_display.o \
+	  intel_fbc.o \
 	  intel_fifo_underrun.o \
 	  intel_frontbuffer.o \
 	  intel_modes.o \