sysctl: remove redundant ret assignment

sysctl: remove redundant ret assignment

Subsequent if judgments will assign new values to ret, so the statement
here should be deleted

The clang_analyzer complains as follows:

  fs/proc/proc_sysctl.c:
  Value stored to 'ret' is never read

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: luo penghao <[email protected]>
Reported-by: Zeal Robot <[email protected]>
Acked-by: Luis Chamberlain <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>