System emulation should provide access to all registers, userspace
emulation should only provide access to unprivileged registers.
Record register flags from GDB register map definition, calculate both
num_regs and num_core_regs if either is zero. Use num_regs in system
emulation, num_core_regs in userspace emulation gdbstub.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
1b7b26e474