gpio/omap: cleanup show revision, remove cpu_is checks, display only once

Remove cpu_is_* checks from gpio_show_revision() by passing in the
revision address offset from platform data.  SoCs with no revision
register (15xx, 7xx, and all MPUIOs) use -1 (actually, USHRT_MAX) to
signify no register.

While here, all GPIO banks are assumed to be the same revision, so fix
show_revision() to only show the revision for the first bank it finds.
This removes duplicate GPIO revision prints during boot.

Thanks to Charulatha V <charu@ti.com> for finding/fixing a few -1s
that were missed in the original patch.

Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap1/gpio15xx.c

@@ -35,6 +35,7 @@ static struct __initdata resource omap15xx_mpu_gpio_resources[] = {
 };
 
 static struct omap_gpio_reg_offs omap15xx_mpuio_regs = {
+	.revision       = USHRT_MAX,
 	.direction	= OMAP_MPUIO_IO_CNTL,
 	.datain		= OMAP_MPUIO_INPUT_LATCH,
 	.dataout	= OMAP_MPUIO_OUTPUT,
@@ -75,6 +76,7 @@ static struct __initdata resource omap15xx_gpio_resources[] = {
 };
 
 static struct omap_gpio_reg_offs omap15xx_gpio_regs = {
+	.revision	= USHRT_MAX,
 	.direction	= OMAP1510_GPIO_DIR_CONTROL,
 	.datain		= OMAP1510_GPIO_DATA_INPUT,
 	.dataout	= OMAP1510_GPIO_DATA_OUTPUT,