[media] rc: allow rc modules to be loaded if rc-main is not a module

rc-main mistakenly uses #ifdef MODULE to determine whether it should
load the rc keymap modules.  This symbol is only defined if rc-main
is being built as a module itself, and bears no relation to whether
the rc keymaps are modules.

Fix this to use CONFIG_MODULES instead.

Fixes: 631493ec ("[media] rc-core: merge rc-map.c into rc-main.c")

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>