ARM: imx: leave irq_base of wm8350_platform_data uninitialized

With commit d1738ae (mfd: Allocate wm835x irq descs dynamically) being
in the tree, there is no need to initialize irq_base field of struct
wm8350_platform_data.  Remove it to save one reference to macro
MXC_BOARD_IRQ_START.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org>

arch/arm/mach-imx/mach-mx31ads.c

@@ -479,7 +479,6 @@ static int mx31_wm8350_init(struct wm8350 *wm8350)
 
 static struct wm8350_platform_data __initdata mx31_wm8350_pdata = {
 	.init = mx31_wm8350_init,
-	.irq_base = MXC_BOARD_IRQ_START + MXC_MAX_EXP_IO_LINES,
 };
 #endif