imx: add support for i.MX7/i.MX8MQ reset controller

Add support for the reset controller that's used on the i.MX7D
and i.MX8MQ.  This will be needed to be able to assert the PCIe
reset pins.  Bindings taken from Linux, driver implementation
mostly taken from Linux and adjusted to U-Boot infrastructure.

Signed-off-by: Patrick Wildt <patrick@blueri.se>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 6ec6f39..976f3a7 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -127,4 +127,11 @@
 	help
 	  Support for reset controller on HiSilicon SoCs.
 
+config RESET_IMX7
+	bool "i.MX7/8 Reset Driver"
+	depends on DM_RESET && (ARCH_MX7 || ARCH_IMX8M)
+	default y
+	help
+	  Support for reset controller on i.MX7/8 SoCs.
+
 endmenu