[S390] fix kvm defines for 31 bit compile

KVM is not available for 31 bit but the KVM defines cause warnings:

arch/s390/include/asm/pgtable.h: In function 'ptep_test_and_clear_user_dirty':
arch/s390/include/asm/pgtable.h:817: warning: integer constant is too large for 'unsigned long' type
arch/s390/include/asm/pgtable.h:818: warning: integer constant is too large for 'unsigned long' type
arch/s390/include/asm/pgtable.h: In function 'ptep_test_and_clear_user_young':
arch/s390/include/asm/pgtable.h:837: warning: integer constant is too large for 'unsigned long' type
arch/s390/include/asm/pgtable.h:838: warning: integer constant is too large for 'unsigned long' type

Add 31 bit versions of the KVM defines to remove the warnings.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>