nds32: Fix bug in bitfield.h

There two bitfield bug for perfomance counter
in bitfield.h:

	PFM_CTL_offSEL1		21 --> 16
	PFM_CTL_offSEL2		27 --> 22

This commit fix it.
Signed-off-by: Nickhu <nickhu@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>

arch/nds32/include/asm/bitfield.h

@@ -692,8 +692,8 @@
 #define PFM_CTL_offKU1		13	/* Enable user mode event counting for PFMC1 */
 #define PFM_CTL_offKU2		14	/* Enable user mode event counting for PFMC2 */
 #define PFM_CTL_offSEL0		15	/* The event selection for PFMC0 */
-#define PFM_CTL_offSEL1		21	/* The event selection for PFMC1 */
-#define PFM_CTL_offSEL2		27	/* The event selection for PFMC2 */
+#define PFM_CTL_offSEL1		16	/* The event selection for PFMC1 */
+#define PFM_CTL_offSEL2		22	/* The event selection for PFMC2 */
 /* bit 28:31 reserved */
 
 #define PFM_CTL_mskEN0		( 0x01  << PFM_CTL_offEN0 )