checkpatch: improve EMBEDDED_FUNCTION_NAME test

The existing behavior relies on patch context to identify function
declarations.  Add the ability to find function declarations when there
is an open brace in column 1.

This finds function declarations only in specific single line forms
where the function name is on a single line like:

  int foo(args...)
  {

and

  int
  foo(args...)
  {

It does not recognize function declarations like:

  int foo(int bar,
          int baz)
  {

Link: http://lkml.kernel.org/r/738d74bbbe1a06b80f11ed504818107c68903095.1488155636.git.joe@perches.com


Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>