iommufd: Fix out_fput in iommufd_fault_alloc()

In the Linux kernel, the following vulnerability has been resolved:

iommufd: Fix out_fput in iommufd_fault_alloc()

As fput() calls the file->f_op->release op, where fault obj and ictx are
getting released, there is no need to release these two after fput() one
more time, which would result in imbalanced refcounts:
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 48 PID: 2369 at lib/refcount.c:31 refcount_warn_saturate+0x60/0x230
Call trace:
refcount_warn_saturate+0x60/0x230 (P)
refcount_warn_saturate+0x60/0x230 (L)
iommufd_fault_fops_release+0x9c/0xe0 [iommufd]
...
VFS: Close: file count is 0 (f_op=iommufd_fops [iommufd])
WARNING: CPU: 48 PID: 2369 at fs/open.c:1507 filp_flush+0x3c/0xf0
Call trace:
filp_flush+0x3c/0xf0 (P)
filp_flush+0x3c/0xf0 (L)
__arm64_sys_close+0x34/0x98
...
imbalanced put on file reference count
WARNING: CPU: 48 PID: 2369 at fs/file.c:74 __file_ref_put+0x100/0x138
Call trace:
__file_ref_put+0x100/0x138 (P)
__file_ref_put+0x100/0x138 (L)
__fput_sync+0x4c/0xd0

Drop those two lines to fix the warnings above.