GekkoDisassembler: standardize SPR names and add missing ones

find ./Source/ -name '*.cpp' -o -name '*.h' | xargs clang-format-19 -i

With the removal of m_flags, dmode is no longer used in fdabc.

With the removal of m_flags, dmode is no longer used in ldst.

With the removal of m_flags, dmode is no longer used in rrn.

With the removal of m_flags, dmode is no longer used in dab.

With the removal of m_flags, dmode is no longer used in nooper.

Writes to m_flags are pointless as it's never read.