reset: Allow building Broadcom STB RESCAL as module

The driver can be built as a module and uses device managed resources.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210924030840.9650-1-f.fainelli@gmail.comSigned-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/Kconfig

@@ -58,7 +58,7 @@ config RESET_BRCMSTB
 	  a SUN_TOP_CTRL_SW_INIT style controller.
 
 config RESET_BRCMSTB_RESCAL
-	bool "Broadcom STB RESCAL reset controller"
+	tristate "Broadcom STB RESCAL reset controller"
 	depends on HAS_IOMEM
 	depends on ARCH_BRCMSTB || COMPILE_TEST
 	default ARCH_BRCMSTB