MIPS: ath25: add basic AR5312 SoC support

Add basic support for Atheros AR5312/AR2312 SoCs: registers definition
file and initial setup code.

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/8238/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/ath25/Makefile b/arch/mips/ath25/Makefile
index 9199fa15..3361619 100644
--- a/arch/mips/ath25/Makefile
+++ b/arch/mips/ath25/Makefile
@@ -9,3 +9,5 @@
 #
 
 obj-y += board.o prom.o devices.o
+
+obj-$(CONFIG_SOC_AR5312) += ar5312.o