staging: rtl8192u: Remove typedef for struct _RT_POWER_SAVE_CONTROL

-Avoid typedefs for structure types to maintain kernel coding style.
-Remove typedefs RT_POWER_SAVE_CONTROL and *PRT_POWER_SAVE_CONTROL of struct _RT_POWER_SAVE_CONTROL.
-Change Structure name _RT_POWER_SAVE_CONTROL to rt_power_save_control to maintain Linux kernel Coding Style.
-Replace occurence of _RT_POWER_SAVE_CONTROL to struct rt_power_save_control.

Signed-off-by: Bhanusree Pola <bhanusreemahesh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>