[gdb] Fix typo in gdb/microblaze-linux-nat.c

Result of:
...
$ codespell --toml gdb/pyproject.toml -w -i3 gdb/microblaze-linux-nat.c
/* Transfering floating-point registers between GDB, inferiors and cores.
	Transfering ==> Transferring (Y/n)
FIXED: gdb/microblaze-linux-nat.c
  gdb/microblaze-linux-nat.c:97: Transfering ==> Transferring
...