[Crash-utility] [RFC] Provide minimal debugging to crash

Hi Sachin and myself have worked on this patch. In case the memory dump is corrupted crash tool exits from execution and we don't have any means to debug the problem. This feature provides minimalistic features to crash and help in debugging even if dump is corrupted. Description of the patch: This patch will provide the minimal functionality in crash tool. This patch has been generated against crash-4.0.6.2. This feature will read the dump, even if it is corrupted. It provides minimal debugging features, as provided by lcrash tool earlier. It provides access to dmesg, symbol information, disassembly and memory read features. You can get into minimal mode by providing "--minimal" option while starting crash eg: crash --minimal <vmlinux> <dump> ======================================================================== Testing: This patch has been tested on the corrupted dump images on z-series machine. 'help' command in the minimal mode gives out put in a line, not like the way out put is generated in the normal mode of operation. Please go through the features and let us know your thoughts ======================================================================== Thanks Yeehaw