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/pasemi_dma.h b/arch/powerpc/include/asm/pasemi_dma.h
index 19fd793..eafa5a5 100644
--- a/arch/powerpc/include/asm/pasemi_dma.h
+++ b/arch/powerpc/include/asm/pasemi_dma.h
@@ -522,7 +522,7 @@
 extern void pasemi_dma_free_buf(struct pasemi_dmachan *chan, int size,
 				dma_addr_t *handle);
 
-/* Routines to allocate flags (events) for channel syncronization */
+/* Routines to allocate flags (events) for channel synchronization */
 extern int  pasemi_dma_alloc_flag(void);
 extern void pasemi_dma_free_flag(int flag);
 extern void pasemi_dma_set_flag(int flag);