kernel: Use pahole from Google prebuilts

This fixes the following warnings:

  13:04:54 Disallowed PATH tool "pahole" used: []string{"pahole", "--version"}
  13:04:54 See https://android.googlesource.com/platform/build/+/master/Changes.md#PATH_Tools for more information.
  "pahole" is not allowed to be used. See https://android.googlesource.com/platform/build/+/master/Changes.md#PATH_Tools for more information.
  /home/bgcngm/android/lineage/kernel/oneplus/sm8550/scripts/pahole-flags.sh: 12: [: Illegal number:
  /home/bgcngm/android/lineage/kernel/oneplus/sm8550/scripts/pahole-flags.sh: 16: [: Illegal number:
  /home/bgcngm/android/lineage/kernel/oneplus/sm8550/scripts/pahole-flags.sh: 20: [: Illegal number:

Change-Id: Ice2a3753301a7b7782037fd35544e2831b258650
diff --git a/config/BoardConfigKernel.mk b/config/BoardConfigKernel.mk
index 0cb175c..a152bac 100644
--- a/config/BoardConfigKernel.mk
+++ b/config/BoardConfigKernel.mk
@@ -219,6 +219,9 @@
 KERNEL_MAKE_FLAGS += M4=$(BUILD_TOP)/prebuilts/build-tools/$(HOST_PREBUILT_TAG)/bin/m4
 TOOLS_PATH_OVERRIDE += BISON_PKGDATADIR=$(BUILD_TOP)/prebuilts/build-tools/common/bison
 
+# Since Linux 5.10, pahole is required
+KERNEL_MAKE_FLAGS += PAHOLE=$(BUILD_TOP)/prebuilts/kernel-build-tools/linux-x86/bin/pahole
+
 # Set the out dir for the kernel's O= arg
 # This needs to be an absolute path, so only set this if the standard out dir isn't used
 OUT_DIR_PREFIX := $(shell echo $(OUT_DIR) | sed -e 's|/target/.*$$||g')