ARM: shmobile: Consolidate the pm code for R-Car Gen2

The pm code for R-Car Gen2 is scatterd in each SoC. These files
(pm-r8a7790.c/pm-r8a7791.c) have some overlap code. This change
consolidate the pm code for R-Car Gen2 into one.

Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/arch/arm/mach-shmobile/rcar-gen2.h b/arch/arm/mach-shmobile/rcar-gen2.h
index ce53cb5..8a66b4a 100644
--- a/arch/arm/mach-shmobile/rcar-gen2.h
+++ b/arch/arm/mach-shmobile/rcar-gen2.h
@@ -5,5 +5,6 @@
 #define MD(nr) BIT(nr)
 u32 rcar_gen2_read_mode_pins(void);
 void rcar_gen2_reserve(void);
+void rcar_gen2_pm_init(void);
 
 #endif /* __ASM_RCAR_GEN2_H__ */