staging: speakup: i18n: fix spelling mistake "phoneticly" -> "phonetically"

There is a spelling mistake in array speakup_default_msgs at index
MSG_FUNCNAME_SPELL_WORD_PHONETICALLY, fix this.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>