MIPS: BCM47XX: Remove CFE support

MIPS: BCM47XX: Remove CFE support

bcm47xx only uses the CFE code for early print to a console, but that
is also possible with a early print serial 8250 driver.

The CFE api init causes hangs somewhere in prom_init_cfe() on some
devices like the Buffalo WHR-HP-G54 and the Asus WL-520GU.
This was reported in https://dev.openwrt.org/ticket/4061 and
https://forum.openwrt.org/viewtopic.php?id=17063

This will remove all the CFE handling code from bcm47xx.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5888/