build: build_id: do not use SOS.6.X

We are stopping lots of different builds for the bringup
phase and added the date.

Specifying as X is not needed anymore.

Change-Id: If4874266f8d9d523a7b40540a65d0af2cd4f4340
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>
diff --git a/build/build_id.mk b/build/build_id.mk
index e70084b..813a0bc 100644
--- a/build/build_id.mk
+++ b/build/build_id.mk
@@ -18,8 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-ifneq ($(TARGET_BUILD_VARIANT),user)
-    BUILD_ID=SOS.6.X.$(shell date +%Y%m%d)
-else
-    BUILD_ID=SOS.6.0.$(shell date +%Y%m%d)
-endif
+BUILD_ID=SOS.6.0.$(shell date +%Y%m%d)