i2c: rcar: update copyright and license information

i2c: rcar: update copyright and license information

Make clear that the driver is GPL v2 only. Remove FSF address. Remove
filename in comment. Update copyright information.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit 3d99beabf17506b9d48461d1677a61a430000ad7)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>