powerpc: Use sizeof(*foo) rather than sizeof(struct foo)

It's slightly less error prone to use sizeof(*foo) rather than
specifying the type.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[mpe: Consolidate into one patch, rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/ps3/mm.c

@@ -524,8 +524,7 @@ static int dma_sb_map_pages(struct ps3_dma_region *r, unsigned long phys_addr,
 	int result;
 	struct dma_chunk *c;
 
-	c = kzalloc(sizeof(struct dma_chunk), GFP_ATOMIC);
-
+	c = kzalloc(sizeof(*c), GFP_ATOMIC);
 	if (!c) {
 		result = -ENOMEM;
 		goto fail_alloc;
@@ -570,8 +569,7 @@ static int dma_ioc0_map_pages(struct ps3_dma_region *r, unsigned long phys_addr,
 
 	DBG(KERN_ERR "%s: phy=%#lx, lpar%#lx, len=%#lx\n", __func__,
 	    phys_addr, ps3_mm_phys_to_lpar(phys_addr), len);
-	c = kzalloc(sizeof(struct dma_chunk), GFP_ATOMIC);
-
+	c = kzalloc(sizeof(*c), GFP_ATOMIC);
 	if (!c) {
 		result = -ENOMEM;
 		goto fail_alloc;