drm/hisilicon: Fix build error of no type of module_init

Add missing include to fix build error:
hibmc_drm_drv.c:385:1: warning: data definition has no type or storage
class [enabled by default]
hibmc_drm_drv.c:385:1: error: type defaults to ‘int’ in declaration
of ‘module_init’ [-Werror=implicit-int]
hibmc_drm_drv.c:385:1: warning: parameter names (without types) in function
of ‘module_exit’ [-Werror=implicit-int]
hibmc_drm_drv.c:385:292:1: warning: parameter names (without types) in
function declaration [enabled by default]

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1597289955-27381-1-git-send-email-tiantao6@hisilicon.com