scripts: improve checkstack
scripts: improve checkstack

Cleanup checkstack script:
  * Turn on strict checking
  * Fix resulting error message because the declaration syntax
    was incorrect.
  * Remove incorrect and misleading use of prototype
     - prototype not required for this type of sort function
       because $a and $b are being used in this contex
     - if prototype was being used it should be for both arguments
  * Use closure for sort function

Signed-off-by: Stephen Hemminger <a072e933f45880fe04500ea083d5c7f6e81a06f0@vyatta.com>
Cc: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>
Cc: Arjan van de Ven <9043bf4b08f6c93a2cb55d98c3494b123858348f@infradead.org>
Cc: Cong Wang <b08afa93ec8eabe95bc97d12956ca699fa65834c@redhat.com>
Cc: Michal Marek <0c835876a532a476f30fdb1f6e963bae6c5a1a04@suse.cz>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Michal Marek <0c835876a532a476f30fdb1f6e963bae6c5a1a04@suse.cz>

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