ARM Samsung: Move s3c pwm driver to pwm framework

Move the driver to drivers/pwm/ and convert it to use the framework.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
[eric@eukrea.com: fix pwmchip_add return code test]
Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>