microblaze: Fix asm/pgtable.h

Function ptep_test_and_clear_young have had wrong the first argument.
It is also necessary to add __HAVE macros for ptep_test_and_clear_young and
ptep_get_and_clear functions.

Error log:
In file included from linux/arch/microblaze/include/asm/pgtable.h:570,
                 from arch/microblaze/mm/pgtable.c:35:
include/asm-generic/pgtable.h:23: error: conflicting types for 'ptep_test_and_clear_young'
linux/arch/microblaze/include/asm/pgtable.h:449: error:
previous definition of 'ptep_test_and_clear_young' was here
include/asm-generic/pgtable.h:73: error: redefinition of 'ptep_get_and_clear'
linux/arch/microblaze/include/asm/pgtable.h:462: error:
previous definition of 'ptep_get_and_clear' was here

Signed-off-by: Michal Simek <monstr@monstr.eu>