sh: Fix up pte_mkhuge() build breakage for SH-5.

Applies the fix from 5b67954e to
pgtable_64.h.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/asm-sh/pgtable_64.h

@@ -137,6 +137,14 @@ static __inline__ void pmd_set(pmd_t *pmdp,pte_t *ptep)
 #define _PAGE_SZHUGE	(_PAGE_SIZE0 | _PAGE_SIZE1)
 #endif
 
+/*
+ * Stub out _PAGE_SZHUGE if we don't have a good definition for it,
+ * to make pte_mkhuge() happy.
+ */
+#ifndef _PAGE_SZHUGE
+# define _PAGE_SZHUGE	(0)
+#endif
+
 /*
  * Default flags for a Kernel page.
  * This is fundametally also SHARED because the main use of this define