Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/arch/powerpc/include/asm/pmac_feature.h b/arch/powerpc/include/asm/pmac_feature.h
index 00eedc5..10902c937 100644
--- a/arch/powerpc/include/asm/pmac_feature.h
+++ b/arch/powerpc/include/asm/pmac_feature.h
@@ -53,8 +53,8 @@
 
 /* Here is the infamous serie of OHare based machines
  */
-#define PMAC_TYPE_COMET			0x20	/* Beleived to be PowerBook 2400 */
-#define PMAC_TYPE_HOOPER		0x21	/* Beleived to be PowerBook 3400 */
+#define PMAC_TYPE_COMET			0x20	/* Believed to be PowerBook 2400 */
+#define PMAC_TYPE_HOOPER		0x21	/* Believed to be PowerBook 3400 */
 #define PMAC_TYPE_KANGA			0x22	/* PowerBook 3500 (first G3) */
 #define PMAC_TYPE_ALCHEMY		0x23	/* Alchemy motherboard base */
 #define PMAC_TYPE_GAZELLE		0x24	/* Spartacus, some 5xxx/6xxx */