proc: Update get proc_pid_cmdline() to use mm.h helpers
proc: Update get proc_pid_cmdline() to use mm.h helpers

Re-factor proc_pid_cmdline() to use get_cmdline() helper
from mm.h.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Richard Guy Briggs <eb4b5bbb4a6cbf3468229148f167a307303eeb1f@redhat.com>

Signed-off-by: William Roberts <759d0895734a44b9d9c9f9a16e0eec3a6e14dc40@tresys.com>
Acked-by: Richard Guy Briggs <eb4b5bbb4a6cbf3468229148f167a307303eeb1f@redhat.com>
Signed-off-by: Eric Paris <b0b36e3cd9ea4e5739ff430a3056fabf2fdb0376@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs