RISC-V: update docs to reflect privileged spec v1.9 has been dropped

After commit d8af286f ("RISC-V: Drop the privileged spec v1.9
support.") has removed support for privileged spec v1.9, this removes
it from the documentation.

References: d8af286f ("RISC-V: Drop the privileged spec v1.9 support.")

gas/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Remove reference to priv spec 1.9.
	* po/fr.po: Same.
	* po/ru.po: Same.
	* po/uk.po: Same.