Add hf iclass creditepurse command to allow crediting the epurse debit value.

include/iclass_cmd.h

@@ -87,6 +87,12 @@ typedef struct {
     uint8_t mac[4];
 } PACKED iclass_writeblock_req_t;
 
+// iCLASS write block request data structure
+typedef struct {
+    iclass_auth_req_t req;
+    uint8_t epurse[4];
+} PACKED iclass_credit_epurse_t;
+
 // iCLASS dump data structure
 typedef struct {
     uint8_t blockno;