ALSA: hda - Update descriptions about new position_fix values

The new values for the recent Intel and AMD chips are missing in the
documentation.  Add the new descriptions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa-configuration.rst

@@ -1001,6 +1001,8 @@ position_fix
     2 = POSBUF: use position buffer,
     3 = VIACOMBO: VIA-specific workaround for capture,
     4 = COMBO: use LPIB for playback, auto for capture stream
+    5 = SKL+: apply the delay calculation available on recent Intel chips
+    6 = FIFO: correct the position with the fixed FIFO size, for recent AMD chips
 probe_mask
     Bitmask to probe codecs (default = -1, meaning all slots);
     When the bit 8 (0x100) is set, the lower 8 bits are used

Documentation/sound/hd-audio/notes.rst

@@ -66,6 +66,11 @@ by comparing both LPIB and position-buffer values.
 ``position_fix=4`` is another combination available for all controllers,
 and uses LPIB for the playback and the position-buffer for the capture
 streams.
+``position_fix=5`` is specific to Intel platforms, so far, for Skylake
+and onward.  It applies the delay calculation for the precise position
+reporting.
+``position_fix=6`` is to correct the position with the fixed FIFO
+size, mainly targeted for the recent AMD controllers.
 0 is the default value for all other
 controllers, the automatic check and fallback to LPIB as described in
 the above.  If you get a problem of repeated sounds, this option might