msm: tracing: disable tracing for the RTB log functions

The function graph tracer causes a kernel crash when enabled. The
counter_get_cntvct_mem and uncached_logk functions call each other
recursively causing a kernel stack overflow. Fix this by annotating
RTB log functions with notrace.

Change-Id: I196a2d554e8210f4a2fb2ee5d489be5b1eb2cab5
CRs-Fixed: 525920
Signed-off-by: Sarang Joshi <spjoshi@codeaurora.org>