procfs: fix /proc/softirqs formatting

procfs: fix /proc/softirqs formatting

The length of the BLOCK_IPOLL string is making i's value be printed too
far to the right.  This patch fixes this and makes the output a bit
neater.

Currently:
                CPU0
      HI:          0
   TIMER:     599792
  NET_TX:          2
  NET_RX:          6
   BLOCK:      80807
BLOCK_IOPOLL:          0
 TASKLET:      20012
   SCHED:          0
 HRTIMER:         63
     RCU:     619279

With patch:
                    CPU0
          HI:          0
       TIMER:     585582
      NET_TX:          2
      NET_RX:          6
       BLOCK:      80320
BLOCK_IOPOLL:          0
     TASKLET:      19287
       SCHED:          0
     HRTIMER:         62
         RCU:     604441

Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Acked-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>