staging: rtl8723bs: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. This performs some refactoring to
remove needless wrapper functions, and adds a pointer back to the desired
adapter.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Shreeya Patel <shreeya.patel23498@gmail.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Himanshu Jha <himanshujha199640@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Derek Robson <robsonde@gmail.com>
Cc: Harsha Sharma <harshasharmaiitr@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>