Add some missing copyright marks

[XVilka]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the documentation and the rizin book with the relevant information (if needed)

Detailed description

Some copyright information was missing, added based on the git history.

Test plan

All green

Closing issues

Partially addresses #683

[codecov]

Codecov Report

Merging #784 (0e8222f) into dev (b035033) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev     #784   +/-   ##
=======================================
  Coverage   42.78%   42.79%           
=======================================
  Files         871      871           
  Lines      316913   316913           
=======================================
+ Hits       135589   135612   +23     
+ Misses     181324   181301   -23     

Impacted Files	Coverage Δ
librz/analysis/arch/hexagon/hexagon_analysis.c	1.67% <ø> (ø)
librz/asm/arch/hexagon/hexagon.c	1.50% <ø> (ø)
librz/asm/arch/hexagon/hexagon_disas.c	0.11% <ø> (ø)
librz/asm/arch/pyc/opcode.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_10.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_11.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_12.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_13.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_14.c	0.00% <ø> (ø)
librz/asm/arch/pyc/opcode_15.c	0.00% <ø> (ø)
... and 44 more

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[ret2libc]

I think I messed up with something at some point... I thought I already added copyright to some of these files :/