Remove extern keyword from function declarations

Function declarations implicitly have external linkage so do not
need the extern keyword.

Change-Id: Ia0549786796d8bf5956487e8996450a0b3d79f32
diff --git a/plat/fvp/drivers/pwrc/fvp_pwrc.h b/plat/fvp/drivers/pwrc/fvp_pwrc.h
index f600a24..ad1ea85 100644
--- a/plat/fvp/drivers/pwrc/fvp_pwrc.h
+++ b/plat/fvp/drivers/pwrc/fvp_pwrc.h
@@ -63,14 +63,14 @@
 /*******************************************************************************
  * Function & variable prototypes
  ******************************************************************************/
-extern int fvp_pwrc_setup(void);
-extern void fvp_pwrc_write_pcoffr(unsigned long);
-extern void fvp_pwrc_write_ppoffr(unsigned long);
-extern void fvp_pwrc_write_pponr(unsigned long);
-extern void fvp_pwrc_set_wen(unsigned long);
-extern void fvp_pwrc_clr_wen(unsigned long);
-extern unsigned int fvp_pwrc_read_psysr(unsigned long);
-extern unsigned int fvp_pwrc_get_cpu_wkr(unsigned long);
+int fvp_pwrc_setup(void);
+void fvp_pwrc_write_pcoffr(unsigned long);
+void fvp_pwrc_write_ppoffr(unsigned long);
+void fvp_pwrc_write_pponr(unsigned long);
+void fvp_pwrc_set_wen(unsigned long);
+void fvp_pwrc_clr_wen(unsigned long);
+unsigned int fvp_pwrc_read_psysr(unsigned long);
+unsigned int fvp_pwrc_get_cpu_wkr(unsigned long);
 
 #endif /*__ASSEMBLY__*/