All callers of mftb() expect 'unsigned long', and the function itself
only returns lower part of the TB so it really is 'unsigned long'
not 'unsigned long long'
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>