We already increment the unicast IPACKETS and OPACKETS counters in the
rx/tx paths, respectively. Multicast packets are counted in the generic
ethernet code. Therefore, we shouldn't increment these counters in
dwc_harvest_stats().

Drop the early return from dwc_rxfinish_one() so that we still count
received packets with e.g. a checksum error.

PR:		263817
Reported by:	Jiahao LI <jiahali@blackberry.com>
Reviewed by:	manu
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D35499