Some tunings of otptear:

- make tearoff_delay_us and tearoff_enabled globals
- use tearoff_hook and remove Dbprintf in critical tearoff timing
- move initial write from MifareU_Otp_Tearoff to CmdHF14AMfuOtpTearoff and make it optional (old behavior was writing initial 00000000 when -d was not provided)
- tearoff: compare with initial write, not with previous tearoff outcome
- rephrase some messages
- track all begin and end of erase and write phases, with quite complex logic to cover multiple cases (starting in middle of erased phase, starting with write 0, ...) and report them
- check against initial write error
- repeat same timing (up to 10x) in case of write/read errors then quit
- typos

include/common.h

@@ -56,6 +56,10 @@ struct version_information {
 #define DBG_EXTENDED      4 // errors + info + debug + breaking debug messages
 extern int DBGLEVEL;
 
+// tear-off
+extern uint16_t tearoff_delay_us;
+extern bool tearoff_enabled;
+
 // reader voltage field detector
 #define MF_MINFIELDV      4000