remove make W=1 warnings

drivers/base/platform-msi.c:336: warning:
Function parameter or member 'is_tree' not described in
'__platform_msi_create_device_domain'

drivers/base/platform-msi.c:336: warning:
expecting prototype for platform_msi_create_device_domain(). Prototype
was for __platform_msi_create_device_domain() instead
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210331232614.304591-7-pierre-louis.bossart@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>