devmatch(8): Respect mask field when matching strings of Z type.

While here, add debug output for this action.

Reviewed by:	imp
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D26823

sbin/devmatch/devmatch.c

@@ -349,7 +349,12 @@ search_hints(const char *bus, const char *dev, const char *pnpinfo)
 						}
 						if (*cp == 'D')
 							break;
+						if (bit >= 0 && ((1 << bit) & mask) == 0)
+							break;
 						s = pnpval_as_str(cp + 2, pnpinfo);
+						if (verbose_flag)
+							printf("Matching %s (%c) table=%s tomatch=%s\n",
+							    cp + 2, *cp, s, val1);
 						if (strcmp(s, val1) != 0)
 							notme++;
 						break;