ARM: multi_v7_defconfig: Make media support modular

Make media support modular to reduce kernel size (-253 KiB):

       text    data     bss     dec     hex   filename
    12451039 1396476  339800 14187315  d87b33 vmlinux.before
    12202692 1387244  338456 13928392  d487c8 vmlinux.after
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/configs/multi_v7_defconfig

@@ -411,7 +411,7 @@ CONFIG_REGULATOR_TPS6586X=y
 CONFIG_REGULATOR_TPS65910=y
 CONFIG_REGULATOR_TWL4030=y
 CONFIG_REGULATOR_VEXPRESS=y
-CONFIG_MEDIA_SUPPORT=y
+CONFIG_MEDIA_SUPPORT=m
 CONFIG_MEDIA_CAMERA_SUPPORT=y
 CONFIG_MEDIA_CONTROLLER=y
 CONFIG_VIDEO_V4L2_SUBDEV_API=y