MIPS: initial infrastructure for Microchip PIC32 architecture

Create initial directory, Kconfigs needed for PIC32 architecture
support. Also add PIC32 specific register definition required for drivers.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 2133e7e..aec5a15 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -8,6 +8,7 @@
 libs-y += arch/mips/lib/
 
 machine-$(CONFIG_SOC_AU1X00) += au1x00
+machine-$(CONFIG_MACH_PIC32) += pic32
 
 machdirs := $(patsubst %,arch/mips/mach-%/,$(machine-y))
 libs-y += $(machdirs)