mmc: Add nvram hostfw directory

Created an nvram directory to store the hypervisor's NVRAM files.
Create a symlink to that directory for apps like PLDM to access it.
Add a dependency to the symlink service to start before the PLDM
services that would make use of the new NVRAM directory start.

Tested: Verified the directory and symlink got created. Verified the
PLDM services started after the symlink one.

Change-Id: I8cdef7cc2176ed10096712918a743efd304df6c1
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/mmc/obmc-flash-bios b/mmc/obmc-flash-bios
index 7d2a1a9..7b1f79b 100644
--- a/mmc/obmc-flash-bios
+++ b/mmc/obmc-flash-bios
@@ -22,6 +22,7 @@
   running_dir="${base_dir}/running"
   prsv_dir="${base_dir}/prsv"
   staging_dir="${base_dir}/staging"
+  nvram_dir="${base_dir}/nvram"
 
   if [ ! -d "${ro_dir}" ]; then
     mkdir -p "${ro_dir}"
@@ -35,6 +36,9 @@
   if [ ! -d "${staging_dir}" ]; then
     mkdir -p "${staging_dir}"
   fi
+  if [ ! -d "${nvram_dir}" ]; then
+    mkdir -p "${nvram_dir}"
+  fi
 
   # Mount the image that corresponds to the boot label as read-only to be used
   # to populate the running directory.