ANDROID: build: Add top level directory to unsafe headers include path

Unsafe header list can be passed to the builds using
user_ddk_unsafe_headers which can be maintained at downstream.
However, there can be name space issues as some of the headers
from diffrent paths use same name, for example

    "drivers/base/regmap/internal.h",
    "drivers/interconnect/internal.h"
    "drivers/regulator/internal.h",
    "fs/proc/internal.h",

To avoid issues with such headers, add top level directory
to the unsafe headers include path with which, modules can
refer to these headers with full path from top level dir.

Bug: 368624818
Change-Id: Ie27983597b6950a8c1e908844bd8aa23371809e0
Signed-off-by: Unnathi Chalicheemala <quic_uchalich@quicinc.com>
Signed-off-by: Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>