ANDROID: Fix adding cflags for CONFIG_AUTOFDO_CLANG

This patch addresses an issue of a backported AutoFDO patch
(aosp/3472210). The original patch relies on the 'is-kernel-object'
check to conditionally apply AutoFDO CFLAGS. However, 'is-kernel-object'
isn't available in kernel 6.6. This patch replaces the
'is-kernel-object' check with a simple 'y' (always true). While this
results in AutoFDO CFLAGS being applied to non-kernel objects, it has no
practical impact. This is because the AutoFDO profile used for
optimization doesn't contain samples for non-kernel objects.

Bug: 392184315
Test: build
Change-Id: I4b635510f44ca4c585861dc507ee4f7a61c2be26
Signed-off-by: Yabin Cui <yabinc@google.com>