meta-romulus: Update VRM control scripts

Romulus VDDR uses different regulator, so the scripts is updated:
1. Remove VDDR related settings in vrm-control.sh
2. Add vrm.sh to invoke vrm-control.sh to set VDN, and invoke i2cset to
set VDDR.

Change-Id: I8be757728833280392328eaf03b3a88b911a4fbd
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/meta-ibm/meta-romulus/recipes-phosphor/chassis/vrm-control/vrm-control@.service b/meta-ibm/meta-romulus/recipes-phosphor/chassis/vrm-control/vrm-control@.service
index 716c526..75c0067 100644
--- a/meta-ibm/meta-romulus/recipes-phosphor/chassis/vrm-control/vrm-control@.service
+++ b/meta-ibm/meta-romulus/recipes-phosphor/chassis/vrm-control/vrm-control@.service
@@ -6,7 +6,7 @@
 Conflicts=obmc-chassis-stop@%i.target
 
 [Service]
-ExecStart={bindir}/vrm-control.sh vdna=0.9 vddra=1.35 vdnb=0.9 vddrb=1.35
+ExecStart={bindir}/vrm.sh
 Type=oneshot
 RemainAfterExit=yes