fuzzers/064-gtx-channel-conf: double specimens from 20 to 40 to resolve some multi candidates features

Signed-off-by: Hans Baier <foss@hans-baier.de>

fuzzers/064-gtx-channel-conf/Makefile

diff --git a/fuzzers/064-gtx-channel-conf/Makefile b/fuzzers/064-gtx-channel-conf/Makefile
index 032e32e..a445582 100644
--- a/fuzzers/064-gtx-channel-conf/Makefile
+++ b/fuzzers/064-gtx-channel-conf/Makefile
@@ -8,7 +8,7 @@
 
 SHELL = bash
 
-N ?= 20
+N ?= 40
 
 BUILD_DIR = build_${XRAY_PART}