Mushu : add I2C_PORT_GPU config
Mushu : add I2C_PORT_GPU config

BUG=b:148968367
BRANCH=none
TEST=make BOARD=mushu

Signed-off-by: loganliao <42d2662f80bcaec802d778ba4aa9d2da497019f3@compal.corp-partner.google.com>
Change-Id: Ib07d46432cf06df6f8816528600650a06f71333d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2094845
Reviewed-by: Logan Liao <3e686fbe841e7f552391c104b5d07238268768cb@compal.corp-partner.google.com>
Reviewed-by: Tim Wawrzynczak <86444811eee8c2cb29e29a251d7a069e64ccc665@chromium.org>
Reviewed-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Tested-by: Logan Liao <3e686fbe841e7f552391c104b5d07238268768cb@compal.corp-partner.google.com>
Commit-Queue: Logan Liao <3e686fbe841e7f552391c104b5d07238268768cb@compal.corp-partner.google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec