Fix misspellings of "whether" in comments.

"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.

Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

arch/powerpc/platforms/powermac/pic.c

@@ -529,7 +529,7 @@ static int __init pmac_pic_probe_mpic(void)
 void __init pmac_pic_init(void)
 {
 	/* We configure the OF parsing based on our oldworld vs. newworld
-	 * platform type and wether we were booted by BootX.
+	 * platform type and whether we were booted by BootX.
 	 */
 #ifdef CONFIG_PPC32
 	if (!pmac_newworld)