ARM: mach-shmobile: add missing GPIO IRQ configuration on mackerel

SDHI0 card-detect GPIO IRQ on mackarel currently works, because it is the
default configuration of IRQ26. However, we should not rely on this and
should configure the function explicitly.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

arch/arm/mach-shmobile/board-mackerel.c

@@ -1512,6 +1512,9 @@ static void __init mackerel_init(void)
 	gpio_request(GPIO_FN_SDHID0_1, NULL);
 	gpio_request(GPIO_FN_SDHID0_0, NULL);
 
+	/* SDHI0 PORT172 card-detect IRQ26 */
+	gpio_request(GPIO_FN_IRQ26_172, NULL);
+
 #if !defined(CONFIG_MMC_SH_MMCIF) && !defined(CONFIG_MMC_SH_MMCIF_MODULE)
 	/* enable SDHI1 */
 	gpio_request(GPIO_FN_SDHICMD1, NULL);