ASoC: wm_adsp: Stop region iteration when the desired region is found

When locating the memory region relating to a coefficient block written
through a bin file we keep processing the list of regions even after we
have found the region we require. This patch adds a break, so we don't
process redundant list items.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>