MIPS: BCM47XX: select NO_EXCEPT_FILL

The kernel is loaded to 0x80001000 so there is some space left for the
exception handlers and the kernel do not have to reserve some extra
space for them.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4747/


Signed-off-by: John Crispin <blogic@openwrt.org>