ftdi: replace proprietary libftd2xx with open-source libftdi1

The Olimex ARM-USB-OCD (and any FT2232 with a custom USB id) couldn't be
enumerated by libftd2xx and needed a manual ftdi_sio unbind. libftdi1
(libusb) opens any VID:PID and auto-detaches the kernel driver.

- rewrite drivers/ftdi_jtag on libftdi1: enumerate a known VID:PID list
  (incl. Olimex 15ba:0003/002b) with per-chip channel counts, open by
  bus/addr + interface, MPSSE via ftdi_write_data/ftdi_read_data (+
  SEND_IMMEDIATE for deterministic reads). MPSSE command building, pin
  map and clocking unchanged.
- CMake: link libftdi1 + libusb-1.0 (pkg-config), drop FTDILIB/FTD2XX
  defines and the libftd2xx.a link; remove the vendored src/libs/libftd2xx.
- registry: NXP LPC2103 (ARM7TDMI-S) entry, IDCODE 0x4F1F0F0F.
- docs updated (deps, layout, decision note, roadmap phase 8).

Validated on hardware: ARM-USB-OCD enumerates, jtag_scan reads the
LPC2103 IDCODE 0x4F1F0F0F, target_info -> [cpu, ARM7] prog: arm_flash.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/modules/drivers/CMakeLists.txt

@@ -12,13 +12,16 @@ if(BS_ENABLE_DIGILENT)
 endif()
 
 include_directories(${DIR_MODULES})
-include_directories(${DIR_LIBS})
-
-add_compile_definitions(FTD2XX_STATIC)
-add_compile_definitions(FTDILIB)
 
 add_library(drivers ${MAIN_SOURCES} ${FTDI_SOURCES} ${GPIO_SOURCES} ${JLINK_SOURCES} ${DIGILENT_SOURCES})
 
+# FTDI MPSSE driver on the open-source libftdi1 (libusb) — no vendored,
+# proprietary libftd2xx. PUBLIC so the executable links them transitively.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(LIBFTDI REQUIRED IMPORTED_TARGET libftdi1)
+pkg_check_modules(LIBUSB  REQUIRED IMPORTED_TARGET libusb-1.0)
+target_link_libraries(drivers PUBLIC PkgConfig::LIBFTDI PkgConfig::LIBUSB)
+
 if(BS_ENABLE_DIGILENT)
     target_link_libraries(drivers PUBLIC ${CMAKE_DL_LIBS})
 endif()

src/modules/jtag_core/CMakeLists.txt

@@ -1,6 +1,5 @@
 set(SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 set(CONFIG_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../config/")
-set(LIB_FTD2XXX "${CMAKE_CURRENT_SOURCE_DIR}/../../libs/libftd2xx/libftd2xx.a")
 
 file(GLOB_RECURSE ALL_SOURCES "*.c")
 
@@ -19,9 +18,6 @@ add_custom_target(
 )
 
 include_directories(${DIR_MODULES})
-include_directories(${DIR_LIBS})
 
 add_library(jtag_core ${ALL_SOURCES})
-add_dependencies(jtag_core prebuild)
-
-target_link_libraries(jtag_core PRIVATE ${LIB_FTD2XXX})
+add_dependencies(jtag_core prebuild)