ibm: romulus: Use v2019.04-aspeed-openbmc u-boot tree

The OpenBMC u-boot tree now has support for the AST2500 based Romulus
and can use a single configuration for NCSI and non-NCSI boards.

Change-Id: I6daa155fcafa0128b119d67bf47cf629ac4b7977
Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/meta-ibm/meta-romulus/conf/machine/romulus.conf b/meta-ibm/meta-romulus/conf/machine/romulus.conf
index c2a24ff..5fe2a9b 100644
--- a/meta-ibm/meta-romulus/conf/machine/romulus.conf
+++ b/meta-ibm/meta-romulus/conf/machine/romulus.conf
@@ -1,10 +1,8 @@
 KMACHINE = "aspeed"
 KERNEL_DEVICETREE = "${KMACHINE}-bmc-opp-${MACHINE}.dtb"
 
-PREFERRED_PROVIDER_virtual/bootloader = "u-boot-aspeed"
-PREFERRED_PROVIDER_u-boot = "u-boot-aspeed"
-PREFERRED_PROVIDER_u-boot-fw-utils = "u-boot-fw-utils-aspeed"
-UBOOT_MACHINE = "ast_g5_ncsi_config"
+UBOOT_MACHINE = "evb-ast2500_defconfig"
+UBOOT_DEVICETREE = "ast2500-romulus"
 
 require conf/machine/include/ast2500.inc
 require conf/machine/include/obmc-bsp-common.inc