staging: wfx: rename "config-file" DT attribute

"config-file" is too broad. Replace it by "silabs,antenna-config-file"
which is more explicit.

The attribute "config-file" is probably not widely used. This patch
obviously breaks setups that use this attribute.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20220113085524.1110708-31-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>