ANDROID: incfs: Add check for ATTR_KILL_SUID and ATTR_MODE in incfs_setattr

Add an explicite check for ATTR_KILL_SUID and ATTR_MODE in incfs_setattr.
Both of these attributes can not be set at the same time, otherwise
notify_change() function will check it and invoke BUG(), crashing
the system.

Bug: 243394930

Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Change-Id: I91080d68efbd62f1441e20a5c02feef3d1b06e4e