ARM: Always build secure_cntvoff.S on ARM V7 to fix shmobile !SMP build

If CONFIG_SMP=n, building a kernel for R-Car Gen2 fails with:

    arch/arm/mach-shmobile/setup-rcar-gen2.o: In function `rcar_gen2_timer_init':
    setup-rcar-gen2.c:(.init.text+0x30): undefined reference to `secure_cntvoff_init'

Indeed, on R-Car Gen2 SoCs, secure_cntvoff_init() is not only needed for
secondary CPUs, but also for the boot CPU.  This is most visible on SoCs
with Cortex A7 cores (e.g. R-Car E2, cfr. commit 9ce3fa68 ("ARM:
shmobile: rcar-gen2: Add CA7 arch_timer initialization for r8a7794")),
but Cortex A15 is affected, too.

Fix this by always providing secure_cntvoff_init() when building for ARM
V7.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 7c607944 ("ARM: smp: Add initialization of CNTVOFF")
Fixes: cad160ed ("ARM: shmobile: Convert file to use cntvoff")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Olof Johansson <olof@lixom.net>