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/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index 76bb195..811f04a 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -86,7 +86,7 @@
 #define PTE_RPN_MASK	(~((1UL<<PTE_RPN_SHIFT)-1))
 #endif
 
-/* _PAGE_CHG_MASK masks of bits that are to be preserved accross
+/* _PAGE_CHG_MASK masks of bits that are to be preserved across
  * pgprot changes
  */
 #define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
@@ -174,7 +174,7 @@
 /*
  * Don't just check for any non zero bits in __PAGE_USER, since for book3e
  * and PTE_64BIT, PAGE_KERNEL_X contains _PAGE_BAP_SR which is also in
- * _PAGE_USER.  Need to explictly match _PAGE_BAP_UR bit in that case too.
+ * _PAGE_USER.  Need to explicitly match _PAGE_BAP_UR bit in that case too.
  */
 #define pte_user(val)		((val & _PAGE_USER) == _PAGE_USER)