watchdog: pcwd_usb: remove unneeded DRIVER_LICENSE #define

There is no need to #define the license of the driver, just put it in
the MODULE_LICENSE() line directly as a text string.

This allows tools that check that the module license matches the source
code license to work properly, as there is no need to unwind the
unneeded dereference, especially when it is defined just a few lines
above from where it is used.

Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Reported-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>