reset: remove redundant $(CONFIG_RESET_CONTROLLER) from Makefile

The directory drivers/reset/ is guarded by CONFIG_RESET_CONTROLLER
in driver/Makefile.

CONFIG_RESET_CONTROLLER is boolean, so it always evaluates to 'y'
in drivers/reset/Makefile.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>