Kconfig: Enable CONFIG_WERROR Building kernel code should not trigger any compiler warnings. Hence enable CONFIG_WERROR. Tested: Built Fusion-Link: fusion2 N/A Google-Bug-Id: 558753346 Change-Id: Iea06f4f94f81b3c2dfd40104fd1d0179b286f2b0 Signed-off-by: Bart Van Assche <bvanassche@google.com>