spi/rockchip: do an error handling in proper time

There was handle_err() callback introduced that is dedicated for error
handling. The patch moves error handling to this callback.

Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>