Staging: rtl8188eu: Remove timer handler macros

After the commit 28af7ea8 ("Staging: rtl8188eu:
Eliminate use of _init_timer"), macros
(RTW_TIMER_HDL_ARGS, RTW_TIMER_HDL_NAME,
RTW_DECLARE_TIMER_HDL) are no longer needed. So,
remove them.

Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>