dt-bindings: remove unimplemented AXI snps,kbbe snps,mb and snps,rb

Remove the AXI snps,kbbe snps,mb and snps,rb properties as they have
not been used, and although the driver parses these, the code hasn't
ever used the parsed result. This parsing has now been removed.

These were introduced by commit afea03656a ("stmmac: rework DMA bus
setting and introduce new platform AXI structure").

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/E1w4ydt-0000000Dlph-3WvI@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/snps,dwmac.yaml

@@ -204,11 +204,8 @@ properties:
         * snps,xit_frm, unlock on WoL
         * snps,wr_osr_lmt, max write outstanding req. limit
         * snps,rd_osr_lmt, max read outstanding req. limit
-        * snps,kbbe, do not cross 1KiB boundary.
         * snps,blen, this is a vector of supported burst length.
         * snps,fb, fixed-burst
-        * snps,mb, mixed-burst
-        * snps,rb, rebuild INCRx Burst
 
   snps,mtl-rx-config:
     $ref: /schemas/types.yaml#/definitions/phandle
@@ -588,11 +585,6 @@ properties:
         description:
           max read outstanding req. limit
 
-      snps,kbbe:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          do not cross 1KiB boundary.
-
       snps,blen:
         $ref: /schemas/types.yaml#/definitions/uint32-array
         description:
@@ -605,16 +597,6 @@ properties:
         description:
           fixed-burst
 
-      snps,mb:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          mixed-burst
-
-      snps,rb:
-        $ref: /schemas/types.yaml#/definitions/flag
-        description:
-          rebuild INCRx Burst
-
 required:
   - compatible
   - reg