[DPP] Add _GENERIC suffix to EASY_CONNECT_EVENT_FAILURE code

Following API council review, rename EASY_CONNECT_EVENT_FAILURE to
EASY_CONNECT_EVENT_FAILURE_GENERIC.

Bug: 122984877
Test: atest DppManagerTest
Change-Id: I4703e7f66b21e7e54dbf1f1059fd1410b7b1bece
2 files changed