[MIPS] Add configuration variables for RM9xxx processor

This patch introduces a number of configuration variables. These allow to
specify presence/absence of integrated peripherals found on the MIPS
RM9xxx processor family, based on the particular processor model used.
Signed-off-by: Thomas Koeller <thomas.koeller@baslerweb.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -126,6 +126,7 @@ config BASLER_EXCITE
 	select IRQ_CPU
 	select IRQ_CPU_RM7K
 	select IRQ_CPU_RM9K
+	select MIPS_RM9122
 	select SYS_HAS_CPU_RM9000
 	select SYS_SUPPORTS_32BIT_KERNEL
 	select SYS_SUPPORTS_64BIT_KERNEL
@@ -973,6 +974,12 @@ config MIPS_TX3927
 	bool
 	select HAS_TXX9_SERIAL
 
+config MIPS_RM9122
+	bool
+	select SERIAL_RM9000
+	select GPI_RM9000
+	select WDT_RM9000
+
 config PCI_MARVELL
 	bool
 
@@ -1023,6 +1030,15 @@ config EMMA2RH
 	depends on MARKEINS
 	default y
 
+config SERIAL_RM9000
+	bool
+
+config GPI_RM9000
+	bool
+
+config WDT_RM9000
+	bool
+
 #
 # Unfortunately not all GT64120 systems run the chip at the same clock.
 # As the user for the clock rate and try to minimize the available options.