Make Coverity more happy with r334545

Make Coverity more happy with r334545

Coverity complains about:

	if (((flags) & M_WAITOK) || _malloc_item != NULL)

saying:

	The expression
		1 /* (2 | 0x100) & 2 */ || _malloc_item != NULL
	is suspicious because it performs a Boolean operation
	on a constant other than 0 or 1.

Although the code is correct, add "!= 0" to make it slightly
more legible and to silence hundreds(?) of Coverity warnings.

Reported by:	Coverity
Discussed with:	mjg
Sponsored by:	Dell EMC