MIPS: remove define-only GDA_MAGIC, previously magic number

The last user was removed in the 2.6.4 "MIPS mega-patch", pre-git

Found with
grep MAGIC Documentation/process/magic-number.rst | while read -r mag _;
do git grep -wF "$mag"  | grep -ve '^Documentation.*magic-number.rst:' \
-qe ':#define '"$mag" || git grep -wF "$mag" | while IFS=: read -r f _;
do sed -i '/\b'"$mag"'\b/d' "$f"; done ; done

Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Link: https://lore.kernel.org/r/c2e7510beebdd698e20d0704712e623fad00fc1c.1663280877.git.nabijaczleweli@nabijaczleweli.xyz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>