Wrap some functions in CONFIG_DPP

The enum dpp_status_error is defined in dpp.h, so these functions
technically shouldn't be defined if CONFIG_DPP is not defined.

Bug: 365585450
Test: m
Change-Id: I0a14fb0a09b2d2d8d0e06e6f8ccd5d5e6b042996
3 files changed