usb: gadget: legacy: nokia: Remove unused static variable 'product_nokia'

usb: gadget: legacy: nokia: Remove unused static variable 'product_nokia'

Looks as though it's never been used.  Driver was introduced in 2010.

Fixes the following W=1 kernel build warning(s):

 drivers/usb/gadget/legacy/nokia.c:65:19: warning: ‘product_nokia’ defined but not used [-Wunused-const-variable=]
 65 | static const char product_nokia[] = NOKIA_LONG_NAME;
 | ^~~~~~~~~~~~~

Cc: Felipe Balbi <balbi@kernel.org>
Cc: Al Borchers <alborchers@steinerpoint.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200706133341.476881-11-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>