tracing: Inline tracing_gen_ctx_flags()

Inline tracing_gen_ctx_flags(). This allows to have one ifdef
CONFIG_TRACE_IRQFLAGS_SUPPORT.

This requires to move `trace_flag_type' so tracing_gen_ctx_flags() can
use it.

Link: https://lkml.kernel.org/r/20210125194511.3924915-3-bigeasy@linutronix.de



Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/20210125140323.6b1ff20c@gandalf.local.home


Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>