avr32: uapi: be sure of "_UAPI" prefix for all guard macros

For all uapi headers, need use "_UAPI" prefix for its guard macro
(which will be stripped by "scripts/headers_installer.sh").

Also remove redundant files (bitsperlong.h, errno.h, fcntl.h, ioctl.h,
ioctls.h, ipcbuf.h, kvm_para.h, mman.h, poll.h, resource.h, siginfo.h,
statfs.h, and unistd.h) which are already in Kbuild.

Also be sure that all "#endif" only have one empty line above, and each
file has guard macro.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Hans-Christian Egtvedt <hegtvedt@cisco.com>