Fix u-boot env var name for Rainier 2U

Change the value of the fitconfig u-boot environment
variable to 'conf@aspeed-bmc-ibm-rainier.dtb'.
This is to match the value used by u-boot to switch to the right
device tree for Rainier 2U.

This also adds Everest to the list of supported systems.

Signed-off-by: Santosh Puranik <santosh.puranik@in.ibm.com>
Change-Id: Ie52bffb1e50c0fd7d081038732e3c5676a69de03
diff --git a/meson_options.txt b/meson_options.txt
index a06c63a..46adce4 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -19,3 +19,4 @@
 option('INVENTORY_JSON_SYM_LINK',type: 'string', value: '/var/lib/vpd/vpd_inventory.json',  description: 'Symbolic link to vpd inventory json.')
 option('INVENTORY_JSON_2U',type: 'string', value: '/usr/share/vpd/50001001.json',  description: 'Inventory JSON for 2U system.')
 option('INVENTORY_JSON_4U',type: 'string', value: '/usr/share/vpd/50001000.json',  description: 'Inventory JSON for 4U system.')
+option('INVENTORY_JSON_EVEREST',type: 'string', value: '/usr/share/vpd/50003000.json',  description: 'Inventory JSON for Everest system.')