rcar_gen3: drivers: pfc: E3: Drop pfc_reg_write() forward declaration

There's no point in having forward declaration just before the function
itself, drop it. No functional change.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: I3cf5bbc388431144c8bbc53ae9f9338276674eee

drivers/staging/renesas/rcar/pfc/E3/pfc_init_e3.c

@@ -287,8 +287,6 @@
 #define MOD_SEL1_SSI9_A		((uint32_t)0U << 4U)
 #define MOD_SEL1_SSI9_B		((uint32_t)1U << 4U)
 
-static void pfc_reg_write(uint32_t addr, uint32_t data);
-
 static void pfc_reg_write(uint32_t addr, uint32_t data)
 {
 	mmio_write_32(PFC_PMMR, ~data);