xtensa_usrregs_info refers to undefined variables xtensa_num_regs and
xtensa_regmap. Drop xtensa_usrregs_info and replace pointer to usrregs
in regs_info with NULL since all registers are read/set through regsets.
2015-04-17 Max Filippov <jcmvbkbc@gmail.com>
gdb/gdbserver/
* linux-xtensa-low.c (xtensa_usrregs_info): Remove.
(regs_info): Replace usrregs pointer with NULL.