MIPS: ath79: use io-accessor macros in pci-ar724x.c

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: René Bolldorf <xsecute@googlemail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3491/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>