Fix gcc-4.9.0 miscompilation of load_balance()  in scheduler

Michel Dänzer and a couple of other people reported inexplicable random
oopses in the scheduler, and the cause turns out to be gcc mis-compiling
the load_balance() function when debugging is enabled.  The gcc bug
apparently goes back to gcc-4.5, but slight optimization changes means
that it now showed up as a problem in 4.9.0 and 4.9.1.

The instruction scheduling problem causes gcc to schedule a spill
operation to before the stack frame has been created, which in turn can
corrupt the spilled value if an interrupt comes in.  There may be other
effects of this bug too, but that's the code generation problem seen in
Michel's case.

This is fixed in current gcc HEAD, but the workaround as suggested by
Markus Trippelsdorf is pretty simple: use -fno-var-tracking-assignments
when compiling the kernel, which disables the gcc code that causes the
problem.  This can result in slightly worse debug information for
variable accesses, but that is infinitely preferable to actual code
generation problems.

Doing this unconditionally (not just for CONFIG_DEBUG_INFO) also allows
non-debug builds to verify that the debug build would be identical: we
can do

    export GCC_COMPARE_DEBUG=1

to make gcc internally verify that the result of the build is
independent of the "-g" flag (it will make the compiler build everything
twice, toggling the debug flag, and compare the results).

Without the "-fno-var-tracking-assignments" option, the build would fail
(even with 4.8.3 that didn't show the actual stack frame bug) with a gcc
compare failure.

See also gcc bugzilla:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801

Reported-by: Michel Dänzer <michel@daenzer.net>
Suggested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
net: wireless: bcmdhd: support Hotspot 2.0 release 1.0

Change-Id: I0d893b85741da628cb5c49c0a1b70c9d2d1ffac9
Signed-off-by: Ecco Park <eccopark@broadcom.com>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
net: wireless: bcmdhd: Add WIPHY_WOWLAN_ANY support

Change-Id: Ia6afe2ebcd0c68622c7f7a1fb36efa62dc009abf
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
net: wireless: bcmdhd: Add support for hidden ssid PNO scan

Changes to support hidden ssid config to be sent to FW. Earlier
all ssids were hard coded as hidden, now only those indicated
as such by supplicant will be.

Change-Id: I927030fe12f162c52c93277b2ebfb4bf55daef4a
Signed-off-by: Ashwin <ashwin.bhat@broadcom.com>