staging: sm750fb: Correctly set CLOCK_PHASE bit of display controller.

Commit 6fba39cf32 ("staging: sm750fb: use BIT macro for
PANEL_DISPLAY_CTRL single-bit fields") accidentally changed the
CLOCK_PHASE logic from '|=' to '=' which clears all the previously set
bits.

Fixes: 6fba39cf32 ("staging: sm750fb: use BIT macro for PANEL_DISPLAY_CTRL single-bit fields")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/sm750fb/ddk750_mode.c

@@ -63,7 +63,7 @@ static unsigned long displayControlAdjust_SM750LE(mode_parameter_t *pModeParam,
 	dispControl |= (CRT_DISPLAY_CTRL_CRTSELECT | CRT_DISPLAY_CTRL_RGBBIT);
 
 	/* Set bit 14 of display controller */
-	dispControl = DISPLAY_CTRL_CLOCK_PHASE;
+	dispControl |= DISPLAY_CTRL_CLOCK_PHASE;
 
 	POKE32(CRT_DISPLAY_CTRL, dispControl);