sparc64: fix typo in pgd_clear()

It really has to be pgdp, not pgd.

It just happend to work since all callers have 'pgd' as an argument.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/include/asm/pgtable_64.h

@@ -826,7 +826,7 @@ static inline unsigned long __pmd_page(pmd_t pmd)
 #define pgd_page_vaddr(pgd)		\
 	((unsigned long) __va(pgd_val(pgd)))
 #define pgd_present(pgd)		(pgd_val(pgd) != 0U)
-#define pgd_clear(pgdp)			(pgd_val(*(pgd)) = 0UL)
+#define pgd_clear(pgdp)			(pgd_val(*(pgdp)) = 0UL)
 
 static inline unsigned long pud_large(pud_t pud)
 {