LU-17027 target: include linux/file.h

LU-17027 target: include linux/file.h

In some 4.x kernels like 4.19 we need to include linux/file.h to
have alloc_file_pseudo() defined.

Change-Id: Ieee8d5ac5b080bd3b5c761f54a5ca2f9581ecfe1
Test-Parameters: trivial
Fixes: ac0380dc519a ("LU-137 osd-ldiskfs: pass through resize ioctl")
Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51943
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>