Simplify and separate out the ftrace README scanning logic into a
separate helper. This is used subsequently to scan for all patterns of
interest and to cache the result.

Since we are only interested in availability of probe argument type x,
we will only scan for that.
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/6dc30edc747ba82a236593be6cf3a046fa9453b5.1488961018.git.naveen.n.rao@linux.vnet.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>