MIPS: replace $(CPU) with Kconfig symbols

Conditionally set head-y and lib-y with boolean Kconfig symbols
for selected CPU. This deprecates the usage of the $(CPU) variable.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

arch/mips/Kconfig

@@ -167,6 +167,14 @@ config SUPPORTS_CPU_MIPS64_R1
 config SUPPORTS_CPU_MIPS64_R2
 	bool
 
+config CPU_MIPS32
+	bool
+	default y if CPU_MIPS32_R1 || CPU_MIPS32_R2
+
+config CPU_MIPS64
+	bool
+	default y if CPU_MIPS64_R1 || CPU_MIPS64_R2
+
 config 32BIT
 	bool
 

arch/mips/Makefile

@@ -2,7 +2,9 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-head-y := arch/mips/cpu/$(CPU)/start.o
+head-$(CONFIG_CPU_MIPS32) := arch/mips/cpu/mips32/start.o
+head-$(CONFIG_CPU_MIPS64) := arch/mips/cpu/mips64/start.o
 
-libs-y += arch/mips/cpu/$(CPU)/
+libs-$(CONFIG_CPU_MIPS32) += arch/mips/cpu/mips32/
+libs-$(CONFIG_CPU_MIPS64) += arch/mips/cpu/mips64/
 libs-y += arch/mips/lib/