quick_dump: Document the register definition format
quick_dump: Document the register definition format

Add a small comment about what the elements in the register
tuple mean.

Signed-off-by: Ville Syrjälä <cd6e8d405ca90be3a03d5427c5b24fbd2d68dcc4@linux.intel.com>
Signed-off-by: Ben Widawsky <73675debcd8a436be48ec22211dcf44fe0df0a64@bwidawsk.net>

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