[lldb] Fix the AArch64 CPSR reg defn to list generic reg
My change to remove an incorrect DWARF register number for
CPSR unintentionally dropped the LLDB_REGNUM_GENERIC_FLAGS
generic reg type in the definitions of cpsr.
We need to have a macro (DEFINE_MISC_REGS) for status/control
registers that have no DWARF/eh_frame and no generic reg num.
I added a new macro, DEFINE_GPR_CPSR, for cpsr which is unique
in having no DWARF/eh_frame numbers but does have a generic
flags reg number.
