ARM: UniPhier: fix SRAM size on support card

The max size of available memories on slot0 and slot1 is 32MB because
 - EA[25] signal is not output on the save-pin mode which is
   used PH1-LD4 or later SoCs.
 - EA[25] signal is not connected by the limitation (or bug?) of
   the PLD logic of DCC support card.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>