[ChangeLog][Platform Specific Changes][Linux] Added support for
cross-compilation for the MIPS CI20.
Task-number: QTBUG-57411
Change-Id: I5be2f53323b1d3c2323cd51064397590c143af1b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
