nand: fix nand read.option parsing

"nand read.part addr off size" would be treated as "nand read.raw addr off 1"
It now fails as intended stating "Unknown nand command suffix '.part'"

Signed-off-by: Harvey Chapman <hchapman@3gfp.com>
diff --git a/common/cmd_nand.c b/common/cmd_nand.c
index 1568594..495610c 100644
--- a/common/cmd_nand.c
+++ b/common/cmd_nand.c
@@ -608,7 +608,7 @@
 		size_t rwsize;
 		ulong pagecount = 1;
 		int read;
-		int raw;
+		int raw = 0;
 
 		if (argc < 4)
 			goto usage;