Invalidate TLB on a local hart.

This was missed in r339367 ("Various fixes for TLB management on RISC-V.").

This fixes operation on lowRISC.

Reviewed by:	jhb
Approved by:	re (gjb)
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D17583

sys/riscv/riscv/pmap.c

@@ -804,6 +804,7 @@ pmap_invalidate_all(pmap_t pmap)
 	 * all sfence_vma requests as global however.
 	 */
 	sbi_remote_sfence_vma(mask.__bits, 0, 0);
+	sfence_vma();
 	sched_unpin();
 }
 #else