[PATCH] powerpc: Make sure we don't create empty lmb regions

To prevent problems later in boot, make sure we don't create zero-size lmb
regions.

I've checked all the callers, and at the moment no one should ever hit this.
All callers use a constant size, or they check the computed size before they
call us.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/lmb.c

@@ -197,6 +197,8 @@ long __init lmb_reserve(unsigned long base, unsigned long size)
 {
 	struct lmb_region *_rgn = &(lmb.reserved);
 
+	BUG_ON(0 == size);
+
 	return lmb_add_region(_rgn, base, size);
 }
 
@@ -227,6 +229,8 @@ unsigned long __init lmb_alloc_base(unsigned long size, unsigned long align,
 	long i, j;
 	unsigned long base = 0;
 
+	BUG_ON(0 == size);
+
 #ifdef CONFIG_PPC32
 	/* On 32-bit, make sure we allocate lowmem */
 	if (max_addr == LMB_ALLOC_ANYWHERE)