u-boot: Specify u-boot package for AST2500 machines

This sets u-boot to the package containing the v2016.07-aspeed-openbmc
branch. This ensures there will be no change if the default changes in
the future.

Change-Id: Iea12e1691dbdda34a3f95d6d0862add0b15bcf37
Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/meta-supermicro/meta-x11spi/conf/machine/x11spi.conf b/meta-supermicro/meta-x11spi/conf/machine/x11spi.conf
index 55b07b0..3cc2bec 100644
--- a/meta-supermicro/meta-x11spi/conf/machine/x11spi.conf
+++ b/meta-supermicro/meta-x11spi/conf/machine/x11spi.conf
@@ -5,6 +5,9 @@
 require conf/machine/include/obmc-bsp-common.inc
 require conf/machine/include/supermicro.inc
 
+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_phy_config"
 
 FLASH_SIZE = "32768"