alsa-lib: Ensure MACHINE_SOCARCH is used consistently
The alsa-lib needs to apply the patches for all i.MX SoCs so using the
'imx' override seems to be the best choice for this specific
use-case.
A missing aspect though was that this should also affect every package
which /depends/ on alsa-lib (e.g: alsa-utils) so it also goes to
MACHINE_SOCARCH architecture fixing the signature change across
different machines.
This fix has been tested using a massive parallel build using
multiconfig.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
