parisc: fix compilation errrors

Commit 0cfaee2a ("include/asm-generic/5level-fixup.h: fix variable
'p4d' set but not used") converted a few functions from macros to static
inline, which causes parisc to complain,

  In file included from include/asm-generic/4level-fixup.h:38:0,
                   from arch/parisc/include/asm/pgtable.h:5,
                   from arch/parisc/include/asm/io.h:6,
                   from include/linux/io.h:13,
                   from sound/core/memory.c:9:
  include/asm-generic/5level-fixup.h:14:18: error: unknown type name 'pgd_t'; did you mean 'pid_t'?
   #define p4d_t    pgd_t
                    ^
  include/asm-generic/5level-fixup.h:24:28: note: in expansion of macro 'p4d_t'
   static inline int p4d_none(p4d_t p4d)
                              ^~~~~

It is because "4level-fixup.h" is included before "asm/page.h" where
"pgd_t" is defined.

Link: http://lkml.kernel.org/r/20190815205305.1382-1-cai@lca.pw
Fixes: 0cfaee2a ("include/asm-generic/5level-fixup.h: fix variable 'p4d' set but not used")
Signed-off-by: Qian Cai <cai@lca.pw>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/parisc/include/asm/pgtable.h

@@ -2,6 +2,7 @@
 #ifndef _PARISC_PGTABLE_H
 #define _PARISC_PGTABLE_H
 
+#include <asm/page.h>
 #include <asm-generic/4level-fixup.h>
 
 #include <asm/fixmap.h>
@@ -98,8 +99,6 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 
 #endif /* !__ASSEMBLY__ */
 
-#include <asm/page.h>
-
 #define pte_ERROR(e) \
 	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
 #define pmd_ERROR(e) \