staging: wilc1000: remove mutex_lock/unlock wrappers

Just call the functions directly.  Also fix the variable types to be
correct, not void *, so we have a semblance of type safety happening
now.

Cc: Johnny Kim <johnny.kim@atmel.com>
Cc: Rachel Kim <rachel.kim@atmel.com>
Cc: Dean Lee <dean.lee@atmel.com>
Cc: Chris Park <chris.park@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>