Rename K0501W to include PCB version

It seems very likely that other versions are not compatible, so make it
clear by including it in the machine type and name. Also update the
documentation.

doc/devices/K0501W_V2_0.md

@@ -1,16 +1,16 @@
-# K0501W
+# K0501W V2.0
 
 This board appears for example in the Davuaz Da-K6501W switch.
 
-It is designed similarly to Hi-K0402WS. However, there are a few differences:
+The general design of the board is similar to Hi-K0402WS V3.0.
+However, there are several differences:
 - One SFP port is replaced by a RTL8221B 2.5G PHY
 - Only one LED is populated for the SFP port
 - No mode switch and only one flash chip
-- Like earlier revisions of the K0402W(S) board, there is no UART
+- Older design using RTL8372 instead of RTL8372N (which also means different GPIO and LED configuration)
+- Like earlier versions of the K0402W(S) board, there is no UART
 
-Even though board looks very similar to K0402W(S), the actual GPIO and LED configuration is quite different.
 All ports and LEDs are supported.
-
 Installation is possible using a flash programmer.
 The BoyaMicro 25Q16BSSIG flash chip is supported by flashprog with chip name "B.25D16AS/BY25Q16BS/BY25Q16ES".
 
@@ -18,6 +18,6 @@ The BoyaMicro 25Q16BSSIG flash chip is supported by flashprog with chip name "B.
 
 The board is marked `PCB-K0501W-V2.0 DIP-K0501WS-V2.0`.
 
-<img src="photos/K0501W/pcb-top.jpg" width="300" />
+<img src="photos/K0501W_V2_0/pcb-top.jpg" width="300" />
 
-<img src="photos/K0501W/pcb-bottom.jpg" width="300" />
+<img src="photos/K0501W_V2_0/pcb-bottom.jpg" width="300" />

machine.c

@@ -409,9 +409,9 @@ void machine_custom_init(void) {
 	reg_bit_set(RTL837X_REG_LED_GLB_IO_EN, 6);
 }
 
-#elif defined MACHINE_K0501W
+#elif defined MACHINE_K0501W_V2_0
 __code const struct machine machine = {
-	.machine_name = "K0501W",
+	.machine_name = "K0501W V2.0",
 	.isRTL8373 = 0,
 	.min_port = 3,
 	.max_port = 8,

machine.h

@@ -17,7 +17,7 @@
 // #define MACHINE_SWTG018AS_A_V_2_0
 // #define MACHINE_SWTGW218AS
 // #define MACHINE_HI_K0402WS
-// #define MACHINE_K0501W
+// #define MACHINE_K0501W_V2_0
 // #define MACHINE_DEFAULT_8C_1SFP
 
 typedef struct {