lib/vdso: Mark do_hres_timens() and do_coarse_timens() __always_inline()

lib/vdso: Mark do_hres_timens() and do_coarse_timens() __always_inline()

In the same spirit as commit c966533f8c6c ("lib/vdso: Mark do_hres()
and do_coarse() as __always_inline"), mark do_hres_timens() and
do_coarse_timens() __always_inline.

The measurement below in on a non timens process, ie on the fastest path.

On powerpc32, without the patch:

clock-gettime-monotonic-raw:    vdso: 1155 nsec/call
clock-gettime-monotonic-coarse:    vdso: 813 nsec/call
clock-gettime-monotonic:    vdso: 1076 nsec/call

With the patch:

clock-gettime-monotonic-raw:    vdso: 1100 nsec/call
clock-gettime-monotonic-coarse:    vdso: 667 nsec/call
clock-gettime-monotonic:    vdso: 1025 nsec/call

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/90dcf45ebadfd5a07f24241551c62f619d1cb930.1617209142.git.christophe.leroy@csgroup.eu