drm/i915/fixed: simplify is_fixed16_zero()

Simply return the condition. No functional changes.
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181116120729.7580-4-jani.nikula@intel.com

drivers/gpu/drm/i915/i915_fixed.h

@@ -14,9 +14,7 @@ typedef struct {
 
 static inline bool is_fixed16_zero(uint_fixed_16_16_t val)
 {
-	if (val.val == 0)
-		return true;
-	return false;
+	return val.val == 0;
 }
 
 static inline uint_fixed_16_16_t u32_to_fixed16(u32 val)