[MIPS] Select ZONE_DMA only if GENERIC_ISA_DMA selected

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index acceae0..f9c4ba5 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -10,7 +10,6 @@
 
 config ZONE_DMA
 	bool
-	default y
 
 choice
 	prompt "System type"
@@ -923,6 +922,7 @@
 
 config GENERIC_ISA_DMA
 	bool
+	select ZONE_DMA
 
 config I8259
 	bool
@@ -946,6 +946,7 @@
 
 config GENERIC_ISA_DMA_SUPPORT_BROKEN
 	bool
+	select ZONE_DMA
 
 #
 # Endianess selection.  Sufficiently obscure so many users don't know what to