intel_reg_dumper: Add a single register decode mode
intel_reg_dumper: Add a single register decode mode

From time to time, one would like to decode a register value that have
been captured at a certain point in time (and say printed out with a
printk). intel_reg_dumper has all the knowledge to do that and this
patch adds a way to ask it to decode a value.

Example usage:

$ ./tools/intel_reg_dumper PCH_PP_CONTROL 0xabcd0002
       PCH_PP_CONTROL: 0xabcd0002 (blacklight disabled, power...

v2: friendlier invocation (Chris Wilson)
v3: remove unecessary casts and use strcasecmp (Jani Nikula)

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

ChrisCummins/intel-gpu-tools,mv0/intel-gpu-tools,rib/intel-gpu-tools,tiagovignatti/intel-gpu-tools,yipdw/intel-gpu-tools,dlespiau/checkmate-test-igt,erikarn/intel-gpu-tools,chenxianqin/intel-gpu-tools,ChrisCummins/intel-gpu-tools,yipdw/intel-gpu-tools,rib/intel-gpu-tools,ChrisCummins/intel-gpu-tools,mv0/intel-gpu-tools,erikarn/intel-gpu-tools,yipdw/intel-gpu-tools,tiagovignatti/intel-gpu-tools,ChrisCummins/intel-gpu-tools,rib/intel-gpu-tools,erikarn/intel-gpu-tools,rib/intel-gpu-tools,yipdw/intel-gpu-tools,chenxianqin/intel-gpu-tools,tiagovignatti/intel-gpu-tools,erikarn/intel-gpu-tools,mv0/intel-gpu-tools,tiagovignatti/intel-gpu-tools,dlespiau/intel-gpu-tools,dlespiau/intel-gpu-tools,dlespiau/intel-gpu-tools,chenxianqin/intel-gpu-tools,dlespiau/checkmate-test-igt,dlespiau/checkmate-test-igt,chenxianqin/intel-gpu-tools,mv0/intel-gpu-tools,dlespiau/checkmate-test-igt