ARM: exynos_defconfig: Compile MAC80211/CFG80211 as modules

MAC80211/CFG80211 framework requires loading regulatory.db from
/lib/firmware directory, so it makes very little sense to have it
built-in. Change it to be built as modules to let it properly load the
needed firmware/db files. As a side effect of this change, the size of
the compressed modules on SquashFS increased significantly from 27MiB
to 38MiB, so increase the size of BLK_DEV_RAM to allow the modules to
fit into it.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>