i2c: designware: Remove dead code in AMD ISP case

i2c: designware: Remove dead code in AMD ISP case

The I²C bus shared with P-Unit is Intel only thing as far as I know.
The AMD ISP driver has no relationship with P-Unit. Remove dead code
that seems copied without much thinking.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Pratap Nirujogi <pratap.nirujogi@amd.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/20260129103439.187478-1-andriy.shevchenko@linux.intel.com