ASoC: Remove unnecessary -codec from cs4270 driver name

Similar to what commit 1e3ad571 (ASoC: Remove redundant -codec from
WM8776 driver name) does for wm8776 driver, this patch does the same
thing for cs4270 driver.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>