MIPS: Fix sign-extension bug in 32-bit kernel on 32-bit hardware.

Probably nobody does arithmetic on cp0 register values so this has never
bitten.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 0ef30c8..32ef8be 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -728,8 +728,8 @@
 			".set\tmips64\n\t"				\
 			"dmfc0\t%M0, " #source "\n\t"			\
 			"dsll\t%L0, %M0, 32\n\t"			\
-			"dsrl\t%M0, %M0, 32\n\t"			\
-			"dsrl\t%L0, %L0, 32\n\t"			\
+			"dsra\t%M0, %M0, 32\n\t"			\
+			"dsra\t%L0, %L0, 32\n\t"			\
 			".set\tmips0"					\
 			: "=r" (__val));				\
 	else								\
@@ -737,8 +737,8 @@
 			".set\tmips64\n\t"				\
 			"dmfc0\t%M0, " #source ", " #sel "\n\t"		\
 			"dsll\t%L0, %M0, 32\n\t"			\
-			"dsrl\t%M0, %M0, 32\n\t"			\
-			"dsrl\t%L0, %L0, 32\n\t"			\
+			"dsra\t%M0, %M0, 32\n\t"			\
+			"dsra\t%L0, %L0, 32\n\t"			\
 			".set\tmips0"					\
 			: "=r" (__val));				\
 	local_irq_restore(__flags);					\