[9610] wlbt: Changed hip4_sampler serialization.

[9610] wlbt: Changed hip4_sampler serialization.

Changed hip4_sampler serialization after hitting
a kernel panic when the spinlock logic gets out of
sync. We still don't know the reason behind the
kernel crash and it would require more research as
the issue occurs around spinlock arm64 logic.

Removed the per device node spinlcok and substituted
by a global spinlock.

This patch also includes an optimization in the
tput update function. If the new tput value (rx/tx)
has no changed from previous sample, do not generate
a new one.

Change-Id: I216097037f024e21fa8f4e598874e683ca436d54
SCSC-Bug-Id: SSB-43554
Signed-off-by: Albert Cano <a.canocamps@samsung.com>