tcpc: Cleanup register dump
tcpc: Cleanup register dump

Shorten the strings used for the TCPC register dump. This change saves
300 bytes of flash space (RO and RW each).

BUG=none
BRANCH=none
TEST=make buildall

Signed-off-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Change-Id: I2740c50a3c0bd88271b1d7d574ef3e877389016c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2209575
Reviewed-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>
Reviewed-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>

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