ANDROID: Kbuild, LLVMLinux: disable clang -Wpointer-bool-conversion

clang warns when converting the address of an array or function to
boolean, since it can never be NULL.  The kernel relies on gcc silently
optimizing these checks away, like when dealing with cpumask_var_t
(which can be either a pointer or an array object, depending on the
value of CONFIG_CPUMASK_OFFSTACK).

Change-Id: I322568a6e467d7278f065503f37dd1dddd340ef4
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: khusika <khusikadhamar@gmail.com>