Delete invalid assignment statements in do_sendfile

Assigning value -EINVAL to "retval" here, but that stored value is
overwritten before it can be used.

retval = -EINVAL;
....
retval = rw_verify_area(WRITE, out.file, &out_pos, count);

value_overwrite: Overwriting previous write to "retval" with value
from rw_verify_area

delete invalid assignment statements
Signed-off-by: n00202754 <nixiaoming@huawei.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/read_write.c

@@ -1407,7 +1407,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 		goto fput_in;
 	if (!(out.file->f_mode & FMODE_WRITE))
 		goto fput_out;
-	retval = -EINVAL;
 	in_inode = file_inode(in.file);
 	out_inode = file_inode(out.file);
 	out_pos = out.file->f_pos;