ASoC: pxa: remove Compulab pxa2xx boards

As these boards have been removed from the pxa tree, amend accordingly
the sound subsystem.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Mike Rapoport <rppt@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200521185140.27276-3-robert.jarzmik@free.fr
Signed-off-by: Mark Brown <broonie@kernel.org>