[ARM] nommu: allows to support module in nommu

A simple patch to support module in nommu mode.
The vmalloc is used instead of __vmalloc_area which depends on CONFIG_MMU.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>