ia64: tools: remove inclusion of ia64-specific version of errno.h header

There is no longer an ia64-specific version of the errno.h header below
arch/ia64/include/uapi/asm/, so trying to build tools/bpf fails with:

    CC       /usr/src/linux/tools/bpf/bpftool/btf_dumper.o
  In file included from /usr/src/linux/tools/include/linux/err.h:8,
                   from btf_dumper.c:11:
  /usr/src/linux/tools/include/uapi/asm/errno.h:13:10: fatal error: ../../../arch/ia64/include/uapi/asm/errno.h: No such file or directory
     13 | #include "../../../arch/ia64/include/uapi/asm/errno.h"
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  compilation terminated.

Thus, just remove the inclusion of the ia64-specific errno.h so that the
build will use the generic errno.h header on this target which was used
there anyway as the ia64-specific errno.h was just a wrapper for the
generic header.

Fixes: c25f867d

 ("ia64: remove unneeded uapi asm-generic wrappers")
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>