remove negative exit codes and other shellchecks in wedge_power.sh

Summary: I was getting shellcheck errors when editing this file in another diff. Negative exit codes and return values are not supported in bash: https://unix.stackexchange.com/questions/418784/what-is-the-min-and-max-values-of-exit-codes-in-linux

Test Plan: This is the only usage of it in code and it doesn't rely on a negative exit code (which couldn't happen anyways): https://www.internalfb.com/code/search?q=WEDGE_POWER_RESET_CMD

Differential Revision: D47138227

Reviewed By: smithscott

fbshipit-source-id: deac069c20862c5edb1fa3fc405cebef3d8dcbef

meta-facebook/meta-wedge100/recipes-utils/openbmc-utils/files/wedge_power.sh

@@ -101,7 +101,7 @@ do_on() {
                 ;;
             *)
                 usage
-                exit -1
+                exit 1
                 ;;
 
         esac
@@ -158,7 +158,7 @@ do_reset() {
                 ;;
             *)
                 usage
-                exit -1
+                exit 1
                 ;;
         esac
     done
@@ -184,7 +184,7 @@ do_reset() {
         if ! wedge_is_us_on; then
             echo "Power resetting microserver that is powered off has no effect."
             echo "Use '$prog on' to power the microserver on"
-            return -1
+            return 1
         fi
         # reset TH first
         reset_brcm.sh
@@ -202,27 +202,27 @@ do_reset() {
 
 if [ $# -lt 1 ]; then
     usage
-    exit -1
+    exit 1
 fi
 
 command="$1"
 shift
 
 case "$command" in
     status)
-        do_status $@
+        do_status "$@"
         ;;
     on)
-        do_on $@
+        do_on "$@"
         ;;
     off)
-        do_off $@
+        do_off "$@"
         ;;
     reset)
-        do_reset $@
+        do_reset "$@"
         ;;
     *)
         usage
-        exit -1
+        exit 1
         ;;
 esac