Some compilers complain when building sound for MOP500:

sound/soc/ux500/mop500.c:27:27:
        fatal error: mop500_ab8500.h: No such file or directory

That file is actually in the local directory rather than include.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>