Add usb-ctrl for USB gadget control

The usb-ctrl is copied from [intel-bmc][1] that creates/destroy USB
mass-storage devices via USB gadget driver.
It supports multiple devices and could be extended with future features.

[1]: https://github.com/Intel-BMC/openbmc/blob/intel/meta-openbmc-mods/meta-common/recipes-core/fw-update/files/usb-ctrl

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: Ie875e7e385ddacef82b7e4d20795c97c001384b3
diff --git a/meson.build b/meson.build
index 5419464..76caf0e 100644
--- a/meson.build
+++ b/meson.build
@@ -6,3 +6,4 @@
 
 subdir('firstboot')
 subdir('http-redirect')
+subdir('usb-ctrl')