soc: renesas: rcar-rst: Fix __iomem on configure call

The configure call back takes a register pointer, so should
have been marked with __iomem. Add this to silence the
following sparse warnings:

    drivers/soc/renesas/rcar-rst.c:33:22: warning: incorrect type in initializer (incompatible argument 1 (different address spaces))
    drivers/soc/renesas/rcar-rst.c:33:22:    expected int ( *configure )( ... )
    drivers/soc/renesas/rcar-rst.c:33:22:    got int ( * )( ... )
    drivers/soc/renesas/rcar-rst.c:97:40: warning: incorrect type in argument 1 (different address spaces)
    drivers/soc/renesas/rcar-rst.c:97:40:    expected void *base
    drivers/soc/renesas/rcar-rst.c:97:40:    got void [noderef] <asn:2> *[assigned] base
Signed-off-by: Ben Dooks (Codethink) <ben.dooks@codethink.co.uk>
Link: https://lore.kernel.org/r/20191218135230.2610161-1-ben.dooks@codethink.co.ukSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/soc/renesas/rcar-rst.c

@@ -21,7 +21,7 @@ static int rcar_rst_enable_wdt_reset(void __iomem *base)
 
 struct rst_config {
 	unsigned int modemr;		/* Mode Monitoring Register Offset */
-	int (*configure)(void *base);	/* Platform specific configuration */
+	int (*configure)(void __iomem *base);	/* Platform specific config */
 };
 
 static const struct rst_config rcar_rst_gen1 __initconst = {