* config/tc-z8k.c (struct z8k_exp): Remove, not used anywhere.
(ctrl_table): Add "flags" keyword and some comments.
(flag_table): Convert to uppercase.
(get_flags_operand): Be case insensitive.
(get_interrupt_operand): Be case insensitive. Support notation
where the inperrupt arguments are separated by commas.
(get_operands): Check whether get_flags_operand consumed all
arguments. Return failure if get_ctrl_operand didn't recognize a
valid control register.
(get_specific): Add case CLASS_CTRL: Test for valid control
register for ldctlb opcode.
(build_bytes): Check for valid control registers.