MIPS: Kconfig: Rename several firmware related config symbols.

With the upcoming merge of the ARC architecture there is a small likelyhood
of conflicting use for the CONFIG_ARC config symbol.  Rename it to
CONFIG_FW_ARC.  Also rename CONFIG_ARC32 to CONFIG_FW_ARC32, CONFIG_ARC64
to CONFIG_FW_ARC64.

For consistence also rename CONFIG_SNIPROM to CONFIG_FW_SNIPROM and
CONFIG_CFE to CONFIG_FW_CFE.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 033395e..f5f873e 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -173,9 +173,9 @@
 #
 # Firmware support
 #
-libs-$(CONFIG_ARC)		+= arch/mips/fw/arc/
-libs-$(CONFIG_CFE)		+= arch/mips/fw/cfe/
-libs-$(CONFIG_SNIPROM)		+= arch/mips/fw/sni/
+libs-$(CONFIG_FW_ARC)		+= arch/mips/fw/arc/
+libs-$(CONFIG_FW_CFE)		+= arch/mips/fw/cfe/
+libs-$(CONFIG_FW_SNIPROM)	+= arch/mips/fw/sni/
 libs-y				+= arch/mips/fw/lib/
 
 #