Add initial port for FT9xx series from Bridgetek.

Add FT90X and FT93X to the list of devices in tusb_option.h. 1700 for FT90x and 1701 for FT93x.
Set endpoint attributes for FT90x and FT93x in dcd_attr.h.
Add FT90x routines for USB device in src/portable/bridgetek/ft90x/dcd_ft90x.c
The location for hardware header files and libraries is hw/mcu/bridgetek/ft90x/hardware. There are no files in the repository, but files will be linked as a submodule in the future. The required files can be copied from or linked to the location "C:/Program Files(x86)/Bridgetek/FT9xx Toolchain/Toolchain/hardware" once the toolchain is installed.
Makefile for the MM900EV1B board for developing with an FT900 device is present. Use "BOARD=mm900ev1b".

src/device/dcd_attr.h

@@ -151,6 +151,13 @@
 #elif TU_CHECK_MCU(GD32VF103)
   #define DCD_ATTR_ENDPOINT_MAX   4
 
+//------------- BridgeTek -------------//
+#elif TU_CHECK_MCU(FT90X)
+  #define DCD_ATTR_ENDPOINT_MAX   8
+
+#elif TU_CHECK_MCU(FT93X)
+  #define DCD_ATTR_ENDPOINT_MAX   16
+
 #else
   #warning "DCD_ATTR_ENDPOINT_MAX is not defined for this MCU, default to 8"
   #define DCD_ATTR_ENDPOINT_MAX   8

src/tusb_option.h

@@ -126,6 +126,10 @@
 // GigaDevice
 #define OPT_MCU_GD32VF103        1600 ///< GigaDevice GD32VF103
 
+// BridgeTek
+#define OPT_MCU_FT90X            1700 ///< BridgeTek FT90x
+#define OPT_MCU_FT93X            1701 ///< BridgeTek FT93x
+
 //--------------------------------------------------------------------+
 // Supported OS
 //--------------------------------------------------------------------+