gpio/omap: remove unnecessary bit-masking for read access

Remove un-necessary bit masking. Since the register are 4 byte aligned
and readl would work as is. The 'enabled' mask is already taking care
to mask for bank width.
Signed-off-by: Charulatha V <charu@ti.com>
Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

drivers/gpio/gpio-omap.c

@@ -576,9 +576,6 @@ static void gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 		enabled = _get_gpio_irqbank_mask(bank);
 		isr_saved = isr = __raw_readl(isr_reg) & enabled;
 
-		if (cpu_is_omap15xx() && (bank->method == METHOD_MPUIO))
-			isr &= 0x0000ffff;
-
 		if (bank->level_mask)
 			level_mask = bank->level_mask & enabled;