phosphor-logging: Add a depends when PELs enabled

When the openpower-pels packageconfig is enabled, add a DEPENDS for
nlohmann-json, as the openpower-pel code uses that.

(From meta-phosphor rev: e64bc0f26668b40b989824d215890b226c52d5ae)

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I5280f90527baa634b8e8c32f4b52d0ec0e296279
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-phosphor/recipes-phosphor/logging/phosphor-logging_git.bb b/meta-phosphor/recipes-phosphor/logging/phosphor-logging_git.bb
index 20fdfde..1340076 100644
--- a/meta-phosphor/recipes-phosphor/logging/phosphor-logging_git.bb
+++ b/meta-phosphor/recipes-phosphor/logging/phosphor-logging_git.bb
@@ -94,7 +94,9 @@
 
 PACKAGECONFIG[openpower-pels] = " \
         --enable-openpower-pel-extension, \
-        --disable-openpower-pel-extension, ,\
+        --disable-openpower-pel-extension, \
+        nlohmann-json, \
+        , \
         "
 
 # Enable install_scripts during native and native SDK build