omap3: igep00x0: Increase malloc() pool size

The IGEPv2 board boot started to fail since the commit afd4f15a ("spi:
omap3_spi: Read platform data in ofdata_to_platdata()"). Because this made
the OMAP3 SPI controller driver to allocate its platform data before doing
a relocation, but the igep0x00 config sets this pool size to just 1 KiB.

Increase the pre-relocation malloc heap size to 16 KiB, as is set by other
OMAP3 boards. This not only restores booting but also makes it consistent.

Leave the SPL pool size to the previous 1 KiB size since 16 KiB may not be
a possible size in that constrained environment and is also the value that
is set by other OMAP3 boards.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Enric Balletbo i Serra <eballetbo@gmail.com>