cmd_nand: slight optimization of nand_dump function

If a non-zero value is given to only_oob argument,
printing the main area is skipped.

With a little modification, we can skip the whole
while loop.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

common/cmd_nand.c

@@ -77,18 +77,21 @@ static int nand_dump(nand_info_t *nand, ulong off, int only_oob, int repeat)
 		goto free_all;
 	}
 	printf("Page %08lx dump:\n", off);
-	i = nand->writesize >> 4;
-	p = datbuf;
 
-	while (i--) {
-		if (!only_oob)
+	if (!only_oob) {
+		i = nand->writesize >> 4;
+		p = datbuf;
+
+		while (i--) {
 			printf("\t%02x %02x %02x %02x %02x %02x %02x %02x"
 			       "  %02x %02x %02x %02x %02x %02x %02x %02x\n",
 			       p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 			       p[8], p[9], p[10], p[11], p[12], p[13], p[14],
 			       p[15]);
-		p += 16;
+			p += 16;
+		}
 	}
+
 	puts("OOB:\n");
 	i = nand->oobsize >> 3;
 	p = oobbuf;