gpio-presence: wants relationship with multi-user

The rule of thumb within OpenBMC is to utilize a wants relationship with
targets, especially the multi-user.target. This follows the general
design of always allowing the system to continue whenever possible.
For example I'm doing some bringup in simulation where these services
are not required, but their failure is impacting my ability to reach
a successful multi-user.target state which impacts other targets that
depend on it.

Tested:
- Verified multi-user.target completes successfully now on my bringup
  system

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: I3f801a400d569cefd62841a4552fd4460bf11545
diff --git a/recipes-phosphor/gpio/phosphor-gpio-monitor_%.bbappend b/recipes-phosphor/gpio/phosphor-gpio-monitor_%.bbappend
index 04399f8..e5af885 100644
--- a/recipes-phosphor/gpio/phosphor-gpio-monitor_%.bbappend
+++ b/recipes-phosphor/gpio/phosphor-gpio-monitor_%.bbappend
@@ -3,7 +3,7 @@
 TMPL_POWERSUPPLY = "phosphor-gpio-presence@.service"
 INSTFMT_POWERSUPPLY = "phosphor-gpio-presence@{0}.service"
 POWERSUPPLY_TGT = "multi-user.target"
-FMT_POWERSUPPLY = "../${TMPL_POWERSUPPLY}:${POWERSUPPLY_TGT}.requires/${INSTFMT_POWERSUPPLY}"
+FMT_POWERSUPPLY = "../${TMPL_POWERSUPPLY}:${POWERSUPPLY_TGT}.wants/${INSTFMT_POWERSUPPLY}"
 
 SYSTEMD_LINK_${PN}-presence_append_ibm-ac-server = " ${@compose_list(d, 'FMT_POWERSUPPLY', 'OBMC_POWER_SUPPLY_INSTANCES')}"
 SYSTEMD_LINK_${PN}-presence_append_mihawk = " ${@compose_list(d, 'FMT_POWERSUPPLY', 'OBMC_POWER_SUPPLY_INSTANCES')}"