i2c: amd-isp: Initialize unique adapter name

Initialize unique name for amdisp i2c adapter, which is used
in the platform driver to detect the matching adapter for
i2c_client creation.

Add definition of amdisp i2c adapter name in a new header file
(include/linux/soc/amd/isp4_misc.h) as it is referred in different
driver modules.

Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Pratap Nirujogi <pratap.nirujogi@amd.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250609155601.1477055-3-pratap.nirujogi@amd.com