hw_hotplug: use exit instead of return

Can only 'return' from a function or sourced script.

Signed-off-by: Karol Latecki <karol.latecki@intel.com>
Change-Id: Ie6104adeec0f07557989d9ba25ca9aa2f563e1d5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12422
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Reviewed-by: Dong Yi <dongx.yi@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: Pawel Piatek <pawelx.piatek@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>

test/nvme/hw_hotplug.sh

@@ -77,7 +77,7 @@ while ! grep "Starting I/O" $testdir/log.txt; do
 done
 
 if ! grep "Starting I/O" $testdir/log.txt; then
-	return 1
+	exit 1
 fi
 
 # Add and remove NVMe with delays between to give some time for IO to proceed
@@ -94,7 +94,7 @@ timing_enter wait_for_example
 
 if ! wait $hotplug_pid; then
 	echo "Hotplug example returned error!"
-	return 1
+	exit 1
 fi
 
 timing_exit wait_for_example