arch/sparc: Add module license and description for fbdev helpers

Add MODULE_LICENSE() and MODULE_DESCRIPTION() for fbdev helpers
on sparc. Fixes the following error:

ERROR: modpost: missing MODULE_LICENSE() in arch/sparc/video/fbdev.o

Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/dri-devel/c525adc9-6623-4660-8718-e0c9311563b8@roeck-us.net/
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 4eec0b30

 ("arch/sparc: Implement fb_is_primary_device() in source file")
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230627145843.31794-1-tzimmermann@suse.de