staging: wilc1000: remove another useless kmalloc wrapper

A static function that just calls kmalloc(), and only used in one place.
It's obvious that the wrappers on wrappers in this driver have never
actually been reviewed...

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>