merge_config.sh: use signal names compatible with dash and bash

The SIGHUP SIGINT and SIGTERM names caused failures when running
merge_config.sh with the dash shell.  Dropping the "SIG" component makes
the script work in both bash and dash.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/merge_config.sh

@@ -24,7 +24,7 @@ clean_up() {
        rm -f $TMP_FILE
        exit
 }
-trap clean_up SIGHUP SIGINT SIGTERM
+trap clean_up HUP INT TERM
 
 usage() {
 	echo "Usage: $0 [OPTIONS] [CONFIG [...]]"