MicroBlaze: Make sure we see memory breakpoints before reading

For linux target, when trying to run a program from gdb, the
following defect is seen:

Program received signal SIGILL, Illegal instruction.
0x48004674 in _dl_debug_state () from target:/lib/ld.so.1

* microblaze-linux-tdep.c (microblaze_linux_memory_remove_breakpoint):
  Call make_scoped_restore_show_memory_breakpoints

Signed-off-by: Gopi Kumar Bulusu <gopi@sankhya.com>
Signed-off-by: Michael J. Eager <eager@eagercon.com>