fsl-dynamic-packagearch.bbclass: Stop using ARM-specific architectures
The code to dynamically assign the architecture does take into account
the default tune so we don't need to include the other architectures
with the SoC suffix into the possible package architecture list.
This allow for the class to be used across different architectures
(such as PowerPC) thus fixing issues while integrating it for QorIQ
usage.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
