dt-bindings: i2c: dw: Remove unused bindings

dt-bindings: i2c: dw: Remove unused bindings

As stated in the d70f60ad964d ("i2c: designware: Remove
not-going-to-be-supported code for Baikal SoC") the Baikal
platforms are not supported and the respective driver code
was removed. Remove the currently unused bindings.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260224115210.3499191-1-andriy.shevchenko@linux.intel.com