phosphor-settings-manager: add `inherit pkgconfig`

The latest Yocto doesn't give us "pkgconfig" for free in many cases.
This repository uses 'PKG_CHECK_MODULES', which relies on pkgconfig.
Add the inherit so that it is available in the configure step.

Change-Id: I1bcd78d11ec01f7724e3d22ea6812dfc223f2c9c
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/meta-phosphor/recipes-phosphor/settings/phosphor-settings-manager_git.bb b/meta-phosphor/recipes-phosphor/settings/phosphor-settings-manager_git.bb
index b3c4918..175e735 100644
--- a/meta-phosphor/recipes-phosphor/settings/phosphor-settings-manager_git.bb
+++ b/meta-phosphor/recipes-phosphor/settings/phosphor-settings-manager_git.bb
@@ -4,7 +4,7 @@
 PR = "r1"
 PV = "1.0+git${SRCPV}"
 
-inherit autotools
+inherit autotools pkgconfig
 inherit obmc-phosphor-dbus-service
 inherit python3native
 inherit phosphor-settings-manager