configs: e850-96: Increase malloc() pool size

configs: e850-96: Increase malloc() pool size

"fastboot flash" tries to malloc 8 MiB buffer after receiving data over
USB and trying to write it to eMMC. Right now only 8.12 MiB malloc is
available for E850-96 overall, which leads to this issue:

    Malloc failed for: CHUNK_TYPE_RAW

Fix it by increasing malloc pool size from 8.12 MiB up to 32 MiB, like
it's done in many other boards using fastboot.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>