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

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 afea03656add ("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>