target/file: Add fd_do_unmap() helper
target/file: Add fd_do_unmap() helper

Add helper fd_do_unmap() to remove duplicated code in
fd_execute_write_same_unmap() and fd_execute_unmap().

Cc: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>
Cc: Martin K. Petersen <0384aaef27f06874adbdb09a807bb339f4aff9fd@oracle.com>
Cc: Nicholas Bellinger <978acd1567d5598152161fdf8bf3ca568f950c9b@linux-iscsi.org>
Signed-off-by: Asias He <7487d0432e24c09ba3f2ff7de44b9eb030d5ae18@redhat.com>
Signed-off-by: Nicholas Bellinger <978acd1567d5598152161fdf8bf3ca568f950c9b@linux-iscsi.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas