drm/i915/display: Remove unused variable in the for loop.

Variable is not used in the loop, and its assignment is redundant too.
So it should be deleted.

The clang_analyzer complains as follows:

drivers/gpu/drm/i915/display/intel_fb.c:1018:3 warning:

Value stored to 'cpp' is never read.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: luo penghao <luo.penghao@zte.com.cn>

drivers/gpu/drm/i915/display/intel_fb.c

@@ -998,7 +998,7 @@ int intel_fill_fb_info(struct drm_i915_private *i915, struct intel_framebuffer *
 	for (i = 0; i < num_planes; i++) {
 		struct fb_plane_view_dims view_dims;
 		unsigned int width, height;
-		unsigned int cpp, size;
+		unsigned int size;
 		u32 offset;
 		int x, y;
 		int ret;
@@ -1015,7 +1015,7 @@ int intel_fill_fb_info(struct drm_i915_private *i915, struct intel_framebuffer *
 				return -EINVAL;
 		}
 
-		cpp = fb->base.format->cpp[i];
+		fb->base.format->cpp[i];
 		intel_fb_plane_dims(fb, i, &width, &height);
 
 		ret = convert_plane_offset_to_xy(fb, i, width, &x, &y);