Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/arch/arm/include/asm/ucontext.h b/arch/arm/include/asm/ucontext.h
index 47f023a..14749ae 100644
--- a/arch/arm/include/asm/ucontext.h
+++ b/arch/arm/include/asm/ucontext.h
@@ -47,7 +47,7 @@
 #endif
 
 #ifdef CONFIG_IWMMXT
-/* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */
+/* iwmmxt_area is 0x98 bytes long, preceded by 8 bytes of signature */
 #define IWMMXT_MAGIC		0x12ef842a
 #define IWMMXT_STORAGE_SIZE	(IWMMXT_SIZE + 8)