These ioctls have been defined in linux/fs.h for a long time

  * BLKGETSIZE64 - <2.6.12 (linux.git epoch)
  * BLKDISCARD - 2.6.28 (d30a2605be9d5132d95944916e8f578fcfe4f976)
  * BLKIOMIN - 2.6.32 (ac481c20ef8f6c6f2be75d581863f40c43874ef7)
  * BLKIOOPT - 2.6.32 (ac481c20ef8f6c6f2be75d581863f40c43874ef7)
  * BLKALIGNOFF - 2.6.32 (ac481c20ef8f6c6f2be75d581863f40c43874ef7)
  * BLKPBSZGET - 2.6.32 (ac481c20ef8f6c6f2be75d581863f40c43874ef7)
  * BLKDISCARDZEROES - 2.6.32 (98262f2762f0067375f83824d81ea929e37e6bfe)
  * BLKSECDISCARD - 2.6.36 (8d57a98ccd0b4489003473979da8f5a1363ba7a3)
  * BLKROTATIONAL - 3.2 (ef00f59c95fe6e002e7c6e3663cdea65e253f4cc)
  * BLKZEROOUT - 3.6 (66ba32dc167202c3cf8c86806581a9393ec7f488)
  * FIBMAP - <2.6.12 (linux.git epoch)
  * FIGETBSZ - <2.6.12 (linux.git epoch)

and when building with latest glibc, we'll see compat definitions
in syscall.c anyway thanks to the previous patch. Thus we can
assume they always exist and remove the conditional checks.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20221004093206.652431-3-berrange@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>