dt-bindings: riscv: add Zve32[xf] Zve64[xfd] ISA extension description

Add description for Zve32x Zve32f Zve64x Zve64f Zve64d ISA extensions.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-4-0711bdd26c12@sifive.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -381,6 +381,36 @@ properties:
             instructions, as ratified in commit 56ed795 ("Update
             riscv-crypto-spec-vector.adoc") of riscv-crypto.
 
+        - const: zve32f
+          description:
+            The standard Zve32f extension for embedded processors, as ratified
+            in commit 6f702a2 ("Vector extensions are now ratified") of
+            riscv-v-spec.
+
+        - const: zve32x
+          description:
+            The standard Zve32x extension for embedded processors, as ratified
+            in commit 6f702a2 ("Vector extensions are now ratified") of
+            riscv-v-spec.
+
+        - const: zve64d
+          description:
+            The standard Zve64d extension for embedded processors, as ratified
+            in commit 6f702a2 ("Vector extensions are now ratified") of
+            riscv-v-spec.
+
+        - const: zve64f
+          description:
+            The standard Zve64f extension for embedded processors, as ratified
+            in commit 6f702a2 ("Vector extensions are now ratified") of
+            riscv-v-spec.
+
+        - const: zve64x
+          description:
+            The standard Zve64x extension for embedded processors, as ratified
+            in commit 6f702a2 ("Vector extensions are now ratified") of
+            riscv-v-spec.
+
         - const: zvfh
           description:
             The standard Zvfh extension for vectored half-precision