checkpatch: allow space in more places before a bracket

checkpatch: allow space in more places before a bracket

Allow a space between a colon and subsequent opening bracket.  This
sequence may occur in inline assembler statements like

	asm(
		"ldr %[out], [%[in]]\n\t"
		: [out] "=r" (ret)
		: [in] "r" (addr)
	);

Allow a space between a comma and subsequent opening bracket.  This
sequence may occur in designated initializers.

To ease backporting the patch, I am also changing the comma-bracket
detection (added in QEMU by commit 409db6eb7199af7a2f09f746bd1b793e9daefe5f)
to use the same regex as brackets and colons (as done independently
by Linux commit daebc534ac15f991961a5bb433e515988220e9bf).

Link: http://lkml.kernel.org/r/20180403191655.23700-1-xypron.glpk@gmx.de
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>