ASoC: wm_adsp: fix error return code in wm_adsp_load()

Fix to return a negative error code from the error handling case
instead of 0 in function wm_adsp_load(), as done elsewhere in this
function.

Fixes: 170b1e12

 ("ASoC: wm_adsp: Add support for new Halo core DSPs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Acked-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20201123133839.4073787-1-luomeng12@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>