reset: RESET_BRCMSTB_RESCAL should depend on ARCH_BRCMSTB

The Broadcom STB RESCAL reset controller is only present on Broadcom
BCM7216 platforms.  Hence add a dependency on ARCH_BRCMSTB, to prevent
asking the user about this driver when configuring a kernel without
BCM7216 support.

Also, merely enabling CONFIG_COMPILE_TEST should not enable additional
code, and thus should not enable this driver by default.

Fixes: 4cf176e5

 ("reset: Add Broadcom STB RESCAL reset controller")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>