staging: wilc1000: replace WILC_WFIDrvHandle by tstrWILC_WFIDrv

The structure, WILC_WFIDrvHandle is used to save the pointer address
for the driver handler which is used throughout the driver but it's
not easy to understand what it means. In addition, it doesn't support
the 64 bit machine and also causes the warnings for the 64 bit build.

This patch replaces the WILC_WFIDrvHandle by the tstrWILC_WFIDrv
because the tstrWILC_WFIDrv is real structure to represent the driver
handler and reduces the 64 bit compile warnings. Also, typecasting to
WILC_WFIDrvHandle is not needed by using tstrWILC_WFIDrv as is.

Signed-off-by: Johnny Kim <johnny.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>