defconfig: Disable ZONE_DMA32 on Lahaina

Disable the DMA zone on for faster memory allocations,
and better memory utilization by merging the memory consumed
by the DMA zone with the normal memory zone.

Change-Id: If3ecf649878ad70bc6045a2c619ef99054ed469d
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>