[ARM] pxa: fix the incorrectly defined drive strength macros for pxa{168,910}

Signed-off-by: Mingwei Wang <mwwang@marvell.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/arch/arm/mach-mmp/include/mach/mfp-pxa910.h b/arch/arm/mach-mmp/include/mach/mfp-pxa910.h
index 48a1cbc..d97de36 100644
--- a/arch/arm/mach-mmp/include/mach/mfp-pxa910.h
+++ b/arch/arm/mach-mmp/include/mach/mfp-pxa910.h
@@ -3,6 +3,11 @@
 
 #include <mach/mfp.h>
 
+#define MFP_DRIVE_VERY_SLOW	(0x0 << 13)
+#define MFP_DRIVE_SLOW		(0x2 << 13)
+#define MFP_DRIVE_MEDIUM	(0x4 << 13)
+#define MFP_DRIVE_FAST		(0x8 << 13)
+
 /* UART2 */
 #define GPIO47_UART2_RXD	MFP_CFG(GPIO47, AF6)
 #define GPIO48_UART2_TXD	MFP_CFG(GPIO48, AF6)