rex: Correct the I2C device address for tcpc_port0
rex: Correct the I2C device address for tcpc_port0

This CL corrects the I2C address for the port 0 TCPC. It was set to
0x73, but that's for address pin being pulled up high, and the address
pin instead is tied low.

BRANCH=none
BUG=b:240434243
TEST=zmake build rex

Signed-off-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@google.com>
Change-Id: I9ed5713bfe355c9fcd769fe0f75ae99b43cacb61
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3830285
Reviewed-by: Madhu P <91daf3dcb52497aaee2bfb2e83426acf7b0e812c@google.com>
Reviewed-by: Fabio Baltieri <1c55e39c05d9ab42261288cf330256b2af6ba179@google.com>
Commit-Queue: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Tested-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>

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