drm/i915: Add more wrapper for fixed_point_16_16 operations

This patch adds few wrapper to perform fixed_point_16_16 operations
mul_round_up_u32_fixed16 : Multiplies u32 and fixed_16_16_t variables
			   & returns u32 result with rounding-up.
mul_fixed16 : Multiplies two fixed_16_16_t variable & returns fixed_16_16
div_round_up_fixed16 : Perform division operation on fixed_16_16_t
		       variables & return u32 result with round-off
div_round_up_u32_fixed16 : devide uint32_t variable by fixed_16_16 variable
			   and round_up the result to uint32_t.

These wrappers will be used by later patches in the series.

Changes from V1:
 - Rename wrapper as per Matt's comment
Changes from V2:
 - Fix indentation

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517115831.13830-3-mahesh1.kumar@intel.com