[MIPS] Enable highmem for all MIPS32 and MIPS64 processors.

    
In case a particular system doesn't support highmem the runtime checks
will ensure nothing bad is going to happen.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -1053,6 +1053,7 @@ config CPU_MIPS32_R1
 	depends on SYS_HAS_CPU_MIPS32_R1
 	select CPU_HAS_PREFETCH
 	select CPU_SUPPORTS_32BIT_KERNEL
+	select CPU_SUPPORTS_HIGHMEM
 	help
 	  Choose this option to build a kernel for release 1 or later of the
 	  MIPS32 architecture.  Most modern embedded systems with a 32-bit
@@ -1069,6 +1070,7 @@ config CPU_MIPS32_R2
 	depends on SYS_HAS_CPU_MIPS32_R2
 	select CPU_HAS_PREFETCH
 	select CPU_SUPPORTS_32BIT_KERNEL
+	select CPU_SUPPORTS_HIGHMEM
 	help
 	  Choose this option to build a kernel for release 2 or later of the
 	  MIPS32 architecture.  Most modern embedded systems with a 32-bit
@@ -1082,6 +1084,7 @@ config CPU_MIPS64_R1
 	select CPU_HAS_PREFETCH
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
+	select CPU_SUPPORTS_HIGHMEM
 	help
 	  Choose this option to build a kernel for release 1 or later of the
 	  MIPS64 architecture.  Many modern embedded systems with a 64-bit
@@ -1099,6 +1102,7 @@ config CPU_MIPS64_R2
 	select CPU_HAS_PREFETCH
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
+	select CPU_SUPPORTS_HIGHMEM
 	help
 	  Choose this option to build a kernel for release 2 or later of the
 	  MIPS64 architecture.  Many modern embedded systems with a 64-bit