[media] platform/Makefile: don't depend on arch to include dirs

Depending on arch configs to include dirs is evil, and makes
harder to change drivers to work with COMPILE_TEST.

Replace them by obj-y.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/Makefile

@@ -44,9 +44,9 @@ obj-$(CONFIG_VIDEO_STI_HDMI_CEC) 	+= sti/cec/
 
 obj-$(CONFIG_VIDEO_STI_DELTA)		+= sti/delta/
 
-obj-$(CONFIG_BLACKFIN)                  += blackfin/
+obj-y                                   += blackfin/
 
-obj-$(CONFIG_ARCH_DAVINCI)		+= davinci/
+obj-y					+= davinci/
 
 obj-$(CONFIG_VIDEO_SH_VOU)		+= sh_vou.o