ARM: configs: at91: enable contiguous memory allocator.

Enable cma to allocate big blocks of memory. The feature is enabled here
and size of cma is passed from the bootargs. IPs like ISC requires
consecutive memory areas to store high resolution frames. The actual size
reserved for cma depends on the product, how much total memory it has and
how far the system is loaded. Considering these factors the value is passed
through the kernel arguments (Eg: cma=128m)

The size is deliberatly set as 0 to disable cma by default. If the size of
0 is selected, CMA is disabled by default, but it can be enabled by passing
cma=size[MG]

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>

Author: bala-gunasundar

arch/arm/configs/at91_dt_defconfig

@@ -33,6 +33,8 @@ CONFIG_MODULE_UNLOAD=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 # CONFIG_SWAP is not set
 CONFIG_SLAB=y
+CONFIG_CMA=y
+CONFIG_CMA_DEBUGFS=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
@@ -296,6 +298,8 @@ CONFIG_CRYPTO_DEV_ATMEL_AES=y
 CONFIG_CRYPTO_DEV_ATMEL_TDES=y
 CONFIG_CRYPTO_DEV_ATMEL_SHA=y
 CONFIG_CRC_CCITT=y
+CONFIG_DMA_CMA=y
+CONFIG_CMA_SIZE_MBYTES=0
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
 # CONFIG_SCHED_DEBUG is not set