Add BOOT_TARGET to hnvram lib.

This is change 1/2 that allows the userspace
hnvram command to r/w BOOT_TARGET.

Change-Id: Ia584337065b377f66393f75fe17dda2b9942777f
(cherry picked from commit bec1407b0ef47dbc93ca6c97e3abe272eeae06f3)
diff --git a/libupgrade/hmx_upgrade_nvram.c b/libupgrade/hmx_upgrade_nvram.c
index 2415b0e..83a4e5c 100644
--- a/libupgrade/hmx_upgrade_nvram.c
+++ b/libupgrade/hmx_upgrade_nvram.c
@@ -169,6 +169,7 @@
   {NVRAM_FIELD_LASER_CHANNEL, "LASER_CHANNEL", HMX_NVRAM_PARTITION_RW, 0},
   {NVRAM_FIELD_MAC_ADDR_PON, "MAC_ADDR_PON", HMX_NVRAM_PARTITION_RO, 0},
   {NVRAM_FIELD_PRODUCTION_UNIT, "PRODUCTION_UNIT", HMX_NVRAM_PARTITION_RW, 0},
+  {NVRAM_FIELD_BOOT_TARGET, "BOOT_TARGET", HMX_NVRAM_PARTITION_RW, 0},
   {NVRAM_FIELD_DUMMY, "DUMMY", HMX_NVRAM_PARTITION_RW, 0}
 };
 /* End typedef */
diff --git a/libupgrade/hmx_upgrade_nvram.h b/libupgrade/hmx_upgrade_nvram.h
index a98a78b..b4ccbd8 100644
--- a/libupgrade/hmx_upgrade_nvram.h
+++ b/libupgrade/hmx_upgrade_nvram.h
@@ -115,6 +115,7 @@
   NVRAM_FIELD_LASER_CHANNEL,
   NVRAM_FIELD_MAC_ADDR_PON,
   NVRAM_FIELD_PRODUCTION_UNIT,
+  NVRAM_FIELD_BOOT_TARGET,
   NVRAM_FIELD_DUMMY = 0xFFFF
 } NVRAM_FIELD_T;