devicetree: edtlib: prefixes which are not vendors are NOT vendors

In Linux, checkpatch.pl relies on the vendor-prefixes.yaml file
to validate manufacturers in compatible strings.
In addition to the vendors defined in vendor-prefixes.txt,
the YAML file includes expressions for "prefixes which are not vendors":
these expressions do NOT define special manufacturers that may appear
in compatible strings, and are never involved as such in DTS files.
We can rather see them as bulk-definitions of JSON/YAML properties
suitable for the dt-schema tools.

OTHO, in Zephyr, checkpatch.pl relies on the vendor-prefixes.txt file,
which does not include these additional prefixes, but edtlib.EDT adds
them as hard-coded special values.

This is confusing, if not incorrect:

- the fact that edtlib.EDT (and thus its client code in the
zephyr/scripts directory) actually allows these vendors
in compatible strings is buried in the source code
- checkpatch.pl (with vendor-prefixes.txt) in Zephyr behaves neither like
checkpatch.pl (with vendor-prefixes.yaml) in Linux, nor like edtlib.EDT
(with _VENDOR_PREFIX_ALLOWED)
- Zephyr should not treat these "prefixes which are not vendors" as
valid manufacturers in compatible strings to begin with

Signed-off-by: Christophe Dufaza <chris@openmarl.org>

scripts/dts/python-devicetree/src/devicetree/edtlib.py

@@ -2247,8 +2247,7 @@ class EDT:
 
                     # As an exception, the root node can have whatever
                     # compatibles it wants. Other nodes get checked.
-                    elif node.path != '/' and \
-                       vendor not in _VENDOR_PREFIX_ALLOWED:
+                    elif node.path != '/':
                         if self._werror:
                             handler_fn: Any = _err
                         else:
@@ -3214,14 +3213,3 @@ _DEFAULT_PROP_SPECS: Dict[str, PropertySpec] = {
     name: PropertySpec(name, _DEFAULT_PROP_BINDING)
     for name in _DEFAULT_PROP_TYPES
 }
-
-# A set of vendor prefixes which are grandfathered in by Linux,
-# and therefore by us as well.
-_VENDOR_PREFIX_ALLOWED: Set[str] = set([
-    "at25", "bm", "devbus", "dmacap", "dsa",
-    "exynos", "fsia", "fsib", "gpio-fan", "gpio-key", "gpio", "gpmc",
-    "hdmi", "i2c-gpio", "keypad", "m25p", "max8952", "max8997",
-    "max8998", "mpmc", "pinctrl-single", "#pinctrl-single", "PowerPC",
-    "pl022", "pxa-mmc", "rcar_sound", "rotary-encoder", "s5m8767",
-    "sdhci", "simple-audio-card", "st-plgpio", "st-spics", "ts",
-])