misc: Port USB251xB/xBi Hi-Speed Hub Controller Driver from Linux

This patch adds a driver for configuration of the Microchip USB251xB/xBi
USB 2.0 hub controller series with USB 2.0 upstream connectivity, SMBus
configuration interface and two to four USB 2.0 downstream ports.

This is ported from Linux as of Linux kernel commit
5c2b9c61ae5d8 ("usb: usb251xb: add boost-up property support")

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 85ae7f6..007c728 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -409,6 +409,15 @@
 	  model. This should only be enabled for testing as it is not useful for
 	  anything else.
 
+config USB_HUB_USB251XB
+	tristate "USB251XB Hub Controller Configuration Driver"
+	depends on I2C
+	help
+	  This option enables support for configuration via SMBus of the
+	  Microchip USB251x/xBi USB 2.0 Hub Controller series. Configuration
+	  parameters may be set in devicetree or platform data.
+	  Say Y or M here if you need to configure such a device via SMBus.
+
 config TWL4030_LED
 	bool "Enable TWL4030 LED controller"
 	help