Eliminate random build failures due to race condition.

Disable inclusion of unused EFI loader as this is the cause of
the build race condition.

Bug: 73019385

Change-Id: Ie2f9ce6492c768c88f89e80262c1feb03750e0c5
(cherry picked from commit a13cd458a13c68c6a971c57300f5b075f7c20355)
diff --git a/configs/picosom-imx6ul_defconfig b/configs/picosom-imx6ul_defconfig
index c326ab6..80e7a88 100644
--- a/configs/picosom-imx6ul_defconfig
+++ b/configs/picosom-imx6ul_defconfig
@@ -35,3 +35,4 @@
 CONFIG_DM=y
 CONFIG_DM_THERMAL=y
 CONFIG_AVB_ATX=y
+# CONFIG_EFI_LOADER is not set