board: adding sipeed Tang Primer 20k

doc/boards.yml

@@ -459,6 +459,13 @@
   Memory: OK
   Flash: IF/EF
 
+- ID: tangprimer20k
+  Description: Sipeed Tang Primer 20k
+  URL: https://wiki.sipeed.com/hardware/en/tang/Tang-Nano-Doc/summary.html
+  FPGA: Gowin Arora GW2A(R)-18(C)
+  Memory: OK
+  Flash: IF
+
 - ID: tec0117
   Description: Trenz Gowin LittleBee (TEC0117)
   URL: https://shop.trenz-electronic.de/en/TEC0117-01-FPGA-Module-with-GOWIN-LittleBee-and-8-MByte-internal-SDRAM

src/board.hpp

@@ -171,6 +171,7 @@ static std::map <std::string, target_board_t> board_list = {
 	JTAG_BOARD("tangnano1k",      "", "ft2232",     0, 0, CABLE_DEFAULT),
 	JTAG_BOARD("tangnano4k",      "", "ft2232",     0, 0, CABLE_DEFAULT),
 	JTAG_BOARD("tangnano9k",      "", "ft2232",     0, 0, CABLE_DEFAULT),
+	JTAG_BOARD("tangprimer20k",   "", "ft2232",     0, 0, CABLE_DEFAULT),
 	JTAG_BOARD("tec0117",         "", "ft2232",     0, 0, CABLE_DEFAULT),
 	DFU_BOARD("orbtrace_dfu",     "", "dfu", 0x1209, 0x3442, 1),
 	JTAG_BITBANG_BOARD("ulx2s",   "", "ft232RL", 0, 0,