perf machine: Create maps for x86 PTI entry trampolines

perf machine: Create maps for x86 PTI entry trampolines

Create maps for x86 PTI entry trampolines, based on symbols found in
kallsyms. It is also necessary to keep track of whether the trampolines
have been mapped particularly when the kernel dso is kcore.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526986485-6562-9-git-send-email-adrian.hunter@intel.com
[ Fix extra_kernel_map_info.cnt designed struct initializer on gcc 4.4.7 (centos:6, etc) ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>