ANDROID: ftrace: vendor hook for ftrace dump on oops

Add following vendor hooks in ftrace oops path to allow
vendor modules to get ftrace buffer data.

1) android_vh_ftrace_oops_enter
2) android_vh_ftrace_size_check
3) android_vh_ftrace_format_check
4) android_vh_ftrace_dump_buffer
5) android_vh_ftrace_oops_exit

Ftrace dump on oops can be controlled with kernel command
line parameter ftrace_dump_on_oops.

Bug: 177387994
Change-Id: I898026bfc3e5c5c5ab1eaa0e86a019a6a720408e
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>