qcacld-3.0: Remove csr_is_p2p_session_connected()

Change I913b6e769f282a0f5a0ddb40e54d294ae07deb55 ("qcacld-3.0: Remove
unused concurrency ini parameters") removed the last client of
csr_is_p2p_session_connected().  Since this function is now unused,
remove it.

Change-Id: Ifd4f4f52bfe6e5be4b472a47cfea765b336a8daf
CRs-Fixed: 2371137
2 files changed