Fix even more -Wdiscarded-qualifers issues

Fedora Rawhide is failing to build due to new glibc header changes
enforcing const-correctness in functions like strchr and memchr.
For example:

../../opcodes/aarch64-dis.c: In function ‘remove_dot_suffix’:
../../opcodes/aarch64-dis.c:4027:7: error: assignment discards ‘const’ qualifier from po
inter target type [-Werror=discarded-qualifiers]
 4027 |   ptr = strchr (inst->opcode->name, '.');
      |       ^
cc1: all warnings being treated as errors

This patch addresses all the discovered issues with --enable-targets=all
and regenerates a few cgen files along the way.