Accessiblity: speakup_decext: specifying the default driver parameters among the module params

This is an enhancement which allows to specify the default driver
parameters among the module parameters.

Adding a default variables to the speakup_decext module
allows to easily set that at boot, rather than
setting the sys variables after boot.
More details can be found here:
https://github.com/linux-speakup/speakup/issues/7



Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20221109215108.7933-6-osmtendev@gmail.com


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