drm/komeda: Off by one in komeda_fb_get_pixel_addr()

The > should be >= to avoid an off by one bug.

Fixes: c46c24bb ("drm/komeda: Add komeda_framebuffer")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>