i386: don't check_pgt_cache in flush_tlb_mm

No other architecture calls check_pgt_cache() from within flush_tlb_mm(),
and i386 is already calling check_pgt_cache() from the usual places,
tlb_finish_mmu() and cpu_idle() (the latter being odd, but not unusual).
flush_tlb_mm() has no business to be freeing pages: remove that line, which
sneaked in with slub's i386 support.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>