On some bug reports the customer is providing only the raw
crash dump but not the ELF and MAP files. Those files are
needed to decode the addresses into symbol names, but the
extremely useful fault reason can still be decoded even
without them.

By making the ELF and MAP arguments optional, one can now
decode the raw dump content into something such as:

--8<--8<--
ELF or MAP file missing, logging raw values.

Crash Info:
	Crash location = <unknown-symbol> [0x000091F4] (based on PC value)
	Caller location = <unknown-symbol> [0x00018E39] (based on LR value)
	Stack Pointer at the time of crash = [200091E8]
	Target and Fault Info:
		Processor Arch: ARM-V7M or above
		Processor Variant: C24
		Forced exception, a fault with configurable priority has been escalated to HardFault
		The processor has attempted to execute an undefined instruction