MIPS: ath25: add common parts

Add common code for Atheros AR5312 and Atheros AR2315 SoCs families.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/8237
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath25/Platform

@@ -0,0 +1,6 @@
+#
+# Atheros AR531X/AR231X WiSoC
+#
+platform-$(CONFIG_ATH25)	+= ath25/
+cflags-$(CONFIG_ATH25)		+= -I$(srctree)/arch/mips/include/asm/mach-ath25
+load-$(CONFIG_ATH25)		+= 0xffffffff80041000