[ipaccess-config] fix bugs in generating the PHYSICAL CONFIG attribute

... while asking the BTS to perform tests for us.  The length of the
ARFCN whitelist is the actual length in bytes, not the number of 16bit
ARFCN numbers.

Also, implement a limit, either by rxlevel or by number of ARFCN
that should end up in the whitelist.
diff --git a/openbsc/src/ipaccess/ipaccess-config.c b/openbsc/src/ipaccess/ipaccess-config.c
index 7b0fd40..f0ad464 100644
--- a/openbsc/src/ipaccess/ipaccess-config.c
+++ b/openbsc/src/ipaccess/ipaccess-config.c
@@ -127,10 +127,10 @@
 	/* Create whitelist from rxlevels */
 	physconf_buf[0] = phys_conf_min[0];
 	physconf_buf[1] = NM_IPAC_EIE_ARFCN_WHITE;
-	num_arfcn = ipac_rxlevstat2whitelist(whitelist, st);
+	num_arfcn = ipac_rxlevstat2whitelist(whitelist, st, 0, 100);
 	arfcnlist_size = num_arfcn * 2;
-	*((uint16_t *) (physconf_buf+2)) = htons(num_arfcn);
-	printf("pc_buf (%s)\n", hexdump(physconf_buf, arfcnlist_size+4));
+	*((uint16_t *) (physconf_buf+2)) = htons(arfcnlist_size);
+	DEBUGP(DNM, "physconf_buf (%s)\n", hexdump(physconf_buf, arfcnlist_size+4));
 	return arfcnlist_size+4;
 }