x86 setup: sizeof() is unsigned, unbreak comparisons

x86 setup: sizeof() is unsigned, unbreak comparisons

patch e6e1ace9904b72478f0c5a5aa7bd174cb6f62561 in mainline.

We use signed values for limit checking since the values can go
negative under certain circumstances.  However, sizeof() is unsigned
and forces the comparison to be unsigned, so move the comparison into
the heap_free() macros so we can ensure it is a signed comparison.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>