ARM: OMAP2: Set PRCM_CLKSRC_CTRL correctly in omap2_enable_osc_ck

This patch fixes an incorrect use of prm_rmw_reg_bits() in
omap2_enable_osc_ck() which is changing bits in PRCM_CLKSRC_CTRL
that are unrelated to the function it is performing.
Signed-off-by: Seth Forshee <seth.forshee@gmail.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/clock24xx.c

@@ -78,7 +78,7 @@ static u32 omap2_get_dpll_rate_24xx(struct clk *tclk)
 static int omap2_enable_osc_ck(struct clk *clk)
 {
 
-	prm_rmw_reg_bits(OMAP_AUTOEXTCLKMODE_MASK, ~OMAP_AUTOEXTCLKMODE_MASK,
+	prm_rmw_reg_bits(OMAP_AUTOEXTCLKMODE_MASK, 0,
 			 OMAP24XX_PRCM_CLKSRC_CTRL);
 
 	return 0;