* i386-linux-nat.c (i386_linux_resume): Use regcache functions
instead of read_register and read_register_pid.
* ia64-linux-nat.c (enable_watchpoints_in_psr): Use REGCACHE
argument instead of PTID. Use regcache functions instead of
read_register_pid.
(ia64_linux_insert_watchpoint): Update call.
(ia64_linux_stopped_data_address): Use regcache functions
instead of read_register_pid and write_register_pid.