ARM: bcm2835: Enable missing CMA settings for VC4 driver

Currently bcm2835_defconfig has CMA disabled which makes the
HDMI output on a Raspberry Pi 1 stop working during boot:

    fb: switching to vc4drmfb from simple
    Console: switching to colour dummy device 80x30
    [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
    [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
    [drm] Driver supports precise vblank timestamp query.
    vc4-drm soc:gpu: failed to allocate buffer with size 9216000
    vc4-drm soc:gpu: Failed to set initial hw configuration.

So enable CMA and DMA_CMA in bcm2835_defconfig.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Fixes: 4400d9ac ("ARM: bcm2835: Enable the VC4 graphics driver in the defconfig")
Reviewed-by: NEric Anholt <eric@anholt.net>

arch/arm/configs/bcm2835_defconfig

 # CONFIG_LOCALVERSION_AUTO is not set
 CONFIG_SYSVIPC=y
-CONFIG_FHANDLE=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
 CONFIG_BSD_PROCESS_ACCT=y
@@ -32,6 +31,7 @@ CONFIG_PREEMPT_VOLUNTARY=y
 CONFIG_AEABI=y
 CONFIG_KSM=y
 CONFIG_CLEANCACHE=y
+CONFIG_CMA=y
 CONFIG_SECCOMP=y
 CONFIG_KEXEC=y
 CONFIG_CRASH_DUMP=y
@@ -52,6 +52,7 @@ CONFIG_MAC80211=y
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 # CONFIG_STANDALONE is not set
+CONFIG_DMA_CMA=y
 CONFIG_SCSI=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_SCSI_CONSTANTS=y
@@ -62,7 +63,6 @@ CONFIG_USB_NET_SMSC95XX=y
 CONFIG_ZD1211RW=y
 CONFIG_INPUT_EVDEV=y
 # CONFIG_LEGACY_PTYS is not set
-# CONFIG_DEVKMEM is not set
 CONFIG_SERIAL_AMBA_PL011=y
 CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_TTY_PRINTK=y