speakup: Fix var_id_t values and thus keymap

commit d97a9d7a ("staging/speakup: Add inflection synth parameter")
introduced a new "inflection" speakup parameter next to "pitch", but
the values of the var_id_t enum are actually used by the keymap tables
so we must not renumber them. The effect was that notably the volume
control shortcut (speakup-1 or 2) was actually changing the inflection.

This moves the INFLECTION value at the end of the var_id_t enum to
fix back the enum values. This also adds a warning about it.

Fixes: d97a9d7a ("staging/speakup: Add inflection synth parameter")
Cc: stable@vger.kernel.org
Reported-by: Kirk Reiser <kirk@reisers.ca>
Reported-by: Gregory Nowak <greg@gregn.net>
Tested-by: Gregory Nowak <greg@gregn.net>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20201012160646.qmdo4eqtj24hpch4@functionSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/accessibility/speakup/spk_types.h

@@ -32,6 +32,10 @@ enum {
 	E_NEW_DEFAULT,
 };
 
+/*
+ * Note: add new members at the end, speakupmap.h depends on the values of the
+ * enum starting from SPELL_DELAY (see inc_dec_var)
+ */
 enum var_id_t {
 	VERSION = 0, SYNTH, SILENT, SYNTH_DIRECT,
 	KEYMAP, CHARS,
@@ -42,9 +46,9 @@ enum var_id_t {
 	SAY_CONTROL, SAY_WORD_CTL, NO_INTERRUPT, KEY_ECHO,
 	SPELL_DELAY, PUNC_LEVEL, READING_PUNC,
 	ATTRIB_BLEEP, BLEEPS,
-	RATE, PITCH, INFLECTION, VOL, TONE, PUNCT, VOICE, FREQUENCY, LANG,
+	RATE, PITCH, VOL, TONE, PUNCT, VOICE, FREQUENCY, LANG,
 	DIRECT, PAUSE,
-	CAPS_START, CAPS_STOP, CHARTAB,
+	CAPS_START, CAPS_STOP, CHARTAB, INFLECTION,
 	MAXVARS
 };