Always use perf kernel on user/userdebug builds

STS testing on Fairphone OS (gms) needs to be done on a userdebug build.
Try getting to a more robust performance with the perf kernel
config, and disabling serial logs.

Issue: FP2P-439
Change-Id: I3ac7eb3ac793e7176e449179911a73b2b96fcabd
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 4a772b1..d6930c6 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -4,17 +4,12 @@
 #
 
 # Check whether to use a perf or a debug kernel configuration.
-# Fairphone Open (sibon) releases are userdebug builds, so use a perf kernel there. Otherwise, both
-# userdebug and eng builds are considered debug configurations.
-KERNEL_USE_PERF_CONFIG=true
-ifeq ($(PRODUCT_FLAVOR), sibon)
-    ifneq (,$(filter eng,$(TARGET_BUILD_VARIANT)))
-        KERNEL_USE_PERF_CONFIG=false
-    endif
+# Always use perf kernel on user and userdebug builds. STS testing etc on
+# fp2-gms userdebuilds runs into performance issues when using the debug kernel.
+ifneq (,$(filter user userdebug,$(TARGET_BUILD_VARIANT)))
+    KERNEL_USE_PERF_CONFIG=true
 else
-    ifneq (,$(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
-        KERNEL_USE_PERF_CONFIG=false
-    endif
+    KERNEL_USE_PERF_CONFIG=false
 endif
 
 #Architecture