powerpc: Remove use of CONFIG_PPC_MERGE

Now that arch/ppc is gone and CONFIG_PPC_MERGE is always set, remove
the dead code associated with !CONFIG_PPC_MERGE from arch/powerpc
and include/asm-powerpc.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 8c8aadb..4ebc52a 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -97,7 +97,7 @@
 
 config VIRQ_DEBUG
 	bool "Expose hardware/virtual IRQ mapping via debugfs"
-	depends on DEBUG_FS && PPC_MERGE
+	depends on DEBUG_FS
 	help
 	  This option will show the mapping relationship between hardware irq
 	  numbers and virtual irq numbers. The mapping is exposed via debugfs