torture: Permit negative kvm.sh --kconfig numberic arguments

This commit loosens the kvm.sh script's regular expressions to permit
negative-valued Kconfig options, for example:

--kconfig CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN=-1

Signed-off-by: Paul E. McKenney <[e-mail]>
Signed-off-by: Frederic Weisbecker <[e-mail]>

tools/testing/selftests/rcutorture/bin/kvm.sh

···
 		fi
 		;;
 	--kconfig|--kconfigs)
-		checkarg --kconfig "(Kconfig options)" $# "$2" '^\(#CHECK#\)\?CONFIG_[A-Z0-9_]\+=\([ynm]\|[0-9]\+\|"[^"]*"\)\( \+\(#CHECK#\)\?CONFIG_[A-Z0-9_]\+=\([ynm]\|[0-9]\+\|"[^"]*"\)\)* *$' '^error$'
+		checkarg --kconfig "(Kconfig options)" $# "$2" '^\(#CHECK#\)\?CONFIG_[A-Z0-9_]\+=\([ynm]\|-\?[0-9]\+\|"[^"]*"\)\( \+\(#CHECK#\)\?CONFIG_[A-Z0-9_]\+=\([ynm]\|-\?[0-9]\+\|"[^"]*"\)\)* *$' '^error$'
 		TORTURE_KCONFIG_ARG="`echo "$TORTURE_KCONFIG_ARG $2" | sed -e 's/^ *//' -e 's/ *$//'`"
 		shift
 		;;