spi: rspi: Remove unneeded semicolon

Introduced by commit 426ef76d ("spi:
rspi: Add DT support").

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>