sleeping in atomic: silence some duplicate warnings

sleeping in atomic: silence some duplicate warnings

The issue here is that Smatch is looking at the whole call tree and you
have stuff like:

void wrapper_function(void)
{
	sleeping_function();
}

void caller(void)
{
	if (foo)
		return;
	wrapper_function();
}

Smatch will print two sleeping in atomic warnings.  One in the caller()
function and another in the wrapper_function().  We only want the warning
from the caller() function.

Signed-off-by: Dan Carpenter <error27@gmail.com>