staging: rtl8188eu: remove pfirmware and fwsize of the hal_data_8188e structure

The pfirmware is used only in rtl88eu_download_fw function
(except the kfree(rtlhal->pfirmware) in netdev_close).

The fwsize not used after initialization at all.

The pfirmvare replaced by fw_data and fwsize removed.

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>