ia64: tools: remove duplicate definition of ia64_mf() on ia64

ia64: tools: remove duplicate definition of ia64_mf() on ia64

The ia64_mf() macro defined in tools/arch/ia64/include/asm/barrier.h is
already defined in <asm/gcc_intrin.h> on ia64 which causes libbpf
failing to build:

    CC       /usr/src/linux/tools/bpf/bpftool//libbpf/staticobjs/libbpf.o
  In file included from /usr/src/linux/tools/include/asm/barrier.h:24,
                   from /usr/src/linux/tools/include/linux/ring_buffer.h:4,
                   from libbpf.c:37:
  /usr/src/linux/tools/include/asm/../../arch/ia64/include/asm/barrier.h:43: error: "ia64_mf" redefined [-Werror]
     43 | #define ia64_mf()       asm volatile ("mf" ::: "memory")
        |
  In file included from /usr/include/ia64-linux-gnu/asm/intrinsics.h:20,
                   from /usr/include/ia64-linux-gnu/asm/swab.h:11,
                   from /usr/include/linux/swab.h:8,
                   from /usr/include/linux/byteorder/little_endian.h:13,
                   from /usr/include/ia64-linux-gnu/asm/byteorder.h:5,
                   from /usr/src/linux/tools/include/uapi/linux/perf_event.h:20,
                   from libbpf.c:36:
  /usr/include/ia64-linux-gnu/asm/gcc_intrin.h:382: note: this is the location of the previous definition
    382 | #define ia64_mf() __asm__ volatile ("mf" ::: "memory")
        |
  cc1: all warnings being treated as errors

Thus, remove the definition from tools/arch/ia64/include/asm/barrier.h.

Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>