MIPS: ath79: remove unused ar7{1x,24}x_pcibios_init functions

The functions are unused now, so remove them.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/4909/


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