ARM i.MX: remove now unnecessary argument from mxc_timer_init

As the timer code now does a clk_get to get its clock we don't
need the struct clk argument anymore.
This also changes the alternative EPIT timer to do a clk_get.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-imx/clk-imx31.c

@@ -175,8 +175,7 @@ int __init mx31_clocks_init(unsigned long fref)
 	mx31_revision();
 	clk_disable_unprepare(clk[iim_gate]);
 
-	mxc_timer_init(NULL, MX31_IO_ADDRESS(MX31_GPT1_BASE_ADDR),
-			MX31_INT_GPT);
+	mxc_timer_init(MX31_IO_ADDRESS(MX31_GPT1_BASE_ADDR), MX31_INT_GPT);
 
 	return 0;
 }