ARM: mxs: Remove MMAP_MIN_ADDR setting from mxs_defconfig

ARM: mxs: Remove MMAP_MIN_ADDR setting from mxs_defconfig

The CONFIG_DEFAULT_MMAP_MIN_ADDR was set to 65536 in mxs_defconfig,
this caused severe breakage of userland applications since the upper
limit for ARM is 32768. By default CONFIG_DEFAULT_MMAP_MIN_ADDR is
set to 4096 and can also be changed via /proc/sys/vm/mmap_min_addr
if needed.

Quoting Russell King [1]:

"4096 is also fine for ARM too. There's not much point in having
defconfigs change it - that would just be pure noise in the config
files."

the CONFIG_DEFAULT_MMAP_MIN_ADDR can be removed from the defconfig
altogether.

This problem was introduced by commit cde7c41 (ARM: configs: add
defconfig for mach-mxs).

[1] http://marc.info/?l=linux-arm-kernel&m=134401593807820&w=2

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: stable@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>