usb_pd_alt_mode_dfp: Move pd_set_svids_discovery
usb_pd_alt_mode_dfp: Move pd_set_svids_discovery

Place it next to the other SVIDs accessor functions.

BUG=none
TEST=make buildall
BRANCH=none

Change-Id: I1ddfd5cc1d4617671e78c6405ddecc3d27be16fc
Signed-off-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2194260
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

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