i2c: designware: Remove not-going-to-be-supported code for Baikal SoC

i2c: designware: Remove not-going-to-be-supported code for Baikal SoC

As noticed in the discussion [1] the Baikal SoC and platforms
are not going to be finalized, hence remove stale code.

Link: https://lore.kernel.org/lkml/22b92ddf-6321-41b5-8073-f9c7064d3432@infradead.org/
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260114081954.252160-2-andriy.shevchenko@linux.intel.com