ARM: omap2plus_defconfig: Enable zram as loadable modules

Enable zram as loadable modules. This allows mounting some part of
memory as swap on low memory devices.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/configs/omap2plus_defconfig

@@ -78,6 +78,8 @@ CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_PARTITION_ADVANCED=y
 CONFIG_BINFMT_MISC=y
 CONFIG_CMA=y
+CONFIG_ZSMALLOC=m
+CONFIG_PGTABLE_MAPPING=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
@@ -150,6 +152,8 @@ CONFIG_MTD_NAND_OMAP2=y
 CONFIG_MTD_NAND_OMAP_BCH=y
 CONFIG_MTD_SPI_NOR=m
 CONFIG_MTD_UBI=y
+CONFIG_ZRAM=m
+CONFIG_ZRAM_WRITEBACK=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_SIZE=16384