sunxi: gpio: Fix up pointer arithmetic

The calls for flipping bits in the Allwinner pin controller registers
were using unnecessarily complex pointer arithmetic.

Improve readability by simplifying the expression.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/arch/arm/mach-sunxi/pinmux.c b/arch/arm/mach-sunxi/pinmux.c
index b2093b6..c95fcee 100644
--- a/arch/arm/mach-sunxi/pinmux.c
+++ b/arch/arm/mach-sunxi/pinmux.c
@@ -14,7 +14,7 @@
 	u32 index = GPIO_CFG_INDEX(bank_offset);
 	u32 offset = GPIO_CFG_OFFSET(bank_offset);
 
-	clrsetbits_le32(&pio->cfg[0] + index, 0xf << offset, val << offset);
+	clrsetbits_le32(&pio->cfg[index], 0xf << offset, val << offset);
 }
 
 void sunxi_gpio_set_cfgpin(u32 pin, u32 val)
@@ -31,7 +31,7 @@
 	u32 offset = GPIO_CFG_OFFSET(bank_offset);
 	u32 cfg;
 
-	cfg = readl(&pio->cfg[0] + index);
+	cfg = readl(&pio->cfg[index]);
 	cfg >>= offset;
 
 	return cfg & 0xf;
@@ -58,7 +58,7 @@
 	u32 index = GPIO_DRV_INDEX(bank_offset);
 	u32 offset = GPIO_DRV_OFFSET(bank_offset);
 
-	clrsetbits_le32(&pio->drv[0] + index, 0x3 << offset, val << offset);
+	clrsetbits_le32(&pio->drv[index], 0x3 << offset, val << offset);
 }
 
 void sunxi_gpio_set_pull(u32 pin, u32 val)
@@ -74,5 +74,5 @@
 	u32 index = GPIO_PULL_INDEX(bank_offset);
 	u32 offset = GPIO_PULL_OFFSET(bank_offset);
 
-	clrsetbits_le32(&pio->pull[0] + index, 0x3 << offset, val << offset);
+	clrsetbits_le32(&pio->pull[index], 0x3 << offset, val << offset);
 }