dt-bindings: vendor-prefixes: Add 'fsi[ab]' to the list of non-vendor prefixes

'fsia' and 'fsib' property prefixes were added as schema in commit
2f52475bac7e ("ASoC: fsi: switch to yaml base Documentation").
Unfortunately to do checks on actual vendor prefixes, we have to track
the handful of prefixes which are not vendors like 'fsia' and 'fsib'.

Fixes: 2f52475bac7e ASoC: fsi: switch to yaml base Documentation
Cc: Kuninori Morimoto <[e-mail]>
Cc: Mark Brown <[e-mail]>
Signed-off-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/vendor-prefixes.yaml

···
 patternProperties:
   # Prefixes which are not vendors, but followed the pattern
   # DO NOT ADD NEW PROPERTIES TO THIS LIST
-  "^(at25|devbus|dmacap|dsa|exynos|gpio-fan|gpio|gpmc|hdmi|i2c-gpio),.*": true
+  "^(at25|devbus|dmacap|dsa|exynos|fsi[ab]|gpio-fan|gpio|gpmc|hdmi|i2c-gpio),.*": true
   "^(keypad|m25p|max8952|max8997|max8998|mpmc),.*": true
   "^(pinctrl-single|#pinctrl-single|PowerPC),.*": true
   "^(pl022|pxa-mmc|rcar_sound|rotary-encoder|s5m8767|sdhci),.*": true