ARM i.MX25: Make timer irq work again

Since i.MX has SPARSE_IRQ enabled the i.MX25 timer is broken. This
is because the internal irqs now start at an offset of NR_IRQS_LEGACY.
The patch fixed this up, but missed the i.MX25 timer which used a
hardcoded value instead of a define. This patch introduces a define
for the timer irq and uses it.

This is broken since introduced with 3.6-rc1:

| commit 8842a9e2869cae14bbb8184004a42fc3070587fb
| Author: Shawn Guo <shawn.guo@linaro.org>
| Date:   Thu Jun 14 11:16:14 2012 +0800
|
|    ARM: imx: enable SPARSE_IRQ for imx platform

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

arch/arm/mach-imx/clk-imx25.c

@@ -241,6 +241,6 @@ int __init mx25_clocks_init(void)
 	clk_register_clkdev(clk[sdma_ahb], "ahb", "imx35-sdma");
 	clk_register_clkdev(clk[iim_ipg], "iim", NULL);
 
-	mxc_timer_init(MX25_IO_ADDRESS(MX25_GPT1_BASE_ADDR), 54);
+	mxc_timer_init(MX25_IO_ADDRESS(MX25_GPT1_BASE_ADDR), MX25_INT_GPT1);
 	return 0;
 }

arch/arm/plat-mxc/include/mach/mx25.h

@@ -98,6 +98,7 @@
 #define MX25_INT_UART1		(NR_IRQS_LEGACY + 45)
 #define MX25_INT_GPIO2		(NR_IRQS_LEGACY + 51)
 #define MX25_INT_GPIO1		(NR_IRQS_LEGACY + 52)
+#define MX25_INT_GPT1		(NR_IRQS_LEGACY + 54)
 #define MX25_INT_FEC		(NR_IRQS_LEGACY + 57)
 
 #define MX25_DMA_REQ_SSI2_RX1	22