meta-ampere: shellcheck: fix up source locations

Many scripts in meta-ampere had `shellcheck source=/dev/null`, which
isn't as useful as putting the real sourced script.  Fix up all of
these in the meta-layer to point to the right script, which as a
side-effect allow a few global-disables to be removed.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Icb43dc76a19edbdada8b4caa6ced57ff07f42d27
diff --git a/meta-ampere/meta-mitchell/recipes-ampere/platform/ampere-platform-init/ampere_bmc_heartbeat.sh b/meta-ampere/meta-mitchell/recipes-ampere/platform/ampere-platform-init/ampere_bmc_heartbeat.sh
index 5ecea31..b9bba7b 100644
--- a/meta-ampere/meta-mitchell/recipes-ampere/platform/ampere-platform-init/ampere_bmc_heartbeat.sh
+++ b/meta-ampere/meta-mitchell/recipes-ampere/platform/ampere-platform-init/ampere_bmc_heartbeat.sh
@@ -1,8 +1,6 @@
 #!/bin/bash
 
-# shellcheck disable=SC2154
-# shellcheck source=/dev/null
-
+# shellcheck source=meta-ampere/meta-mitchell/recipes-ampere/platform/ampere-platform-init/gpio-lib.sh
 source /usr/sbin/gpio-lib.sh
 
 value=0