We were defining TARGET_FS_IOC_GETFLAGS and TARGET_FS_IOC_SETFLAGS
using the host 'long' type in the size field, which meant that
they had the wrong values if the host and guest had different
sized longs. Switch to abi_long instead.

This fixes a bug where these ioctls don't work on 32-bit guests
on 64-bit hosts (and makes the LTP test 'setxattr03' pass
where it did not previously.)

Reported-by: pgndev <pgnet.dev@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>