tools arch: Remove uapi bitsperlong.h of hexagon and microblaze

After the following two commits:

  commit 872e24d5 ("hexagon: remove asm/bitsperlong.h")
  commit 83f0124a ("microblaze: remove asm-generic wrapper headers")

the arch-specific headers of hexagon and microblaze have been removed,
the tools arch uapi headers are useless too, remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>