ARM: 8696/1: mm: Remove dead code in mem_init()

The code in question checks memory constrains to set default policy for
overcommit; however we support page size of 4K only thus condition is
always evaluated to false. Remove that dead code.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>