usb: musb: remove unused variable 'count'

usb: musb: remove unused variable 'count'

The variable count is being initialized and incremented but it is never
actually referenced in any other way. The variable is redundant and can
be removed.

Cleans up clang scan build warning:
drivers/usb/musb/musb_gadget.c:1747:12: warning: variable 'count' set
but not used [-Wunused-but-set-variable]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20240229115548.218713-1-colin.i.king@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>