drm/i915: Round to closest when computing the VGA dotclock for LPT-H

Bspec says we should round to closest when computing the LPT-H VGA
dotclock, so let's do that.

v2: Fix typo in commit message (Paulo)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449260421-14243-1-git-send-email-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -3978,7 +3978,7 @@ static void lpt_program_iclkip(struct drm_crtc *crtc)
 		u32 iclk_pi_range = 64;
 		u32 desired_divisor, msb_divisor_value, pi_value;
 
-		desired_divisor = (iclk_virtual_root_freq / clock);
+		desired_divisor = DIV_ROUND_CLOSEST(iclk_virtual_root_freq, clock);
 		msb_divisor_value = desired_divisor / iclk_pi_range;
 		pi_value = desired_divisor % iclk_pi_range;