ARM: omapl138_lcdk: Increase malloc pool before relocation

Driver model requires a malloc pool to allocate memory before
relocations to operate serial and some other devices.  This patch
increases the pool size to 2K.

Signed-off-by: Adam Ford <aford173@gmail.com>
Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>