target-mips: fix call to memset in soft reset code

target-mips: fix call to memset in soft reset code

Recent versions of GCC report the following error when compiling
target-mips/helper.c:

  qemu/target-mips/helper.c:542:9: warning: ‘memset’ used with length
  equal to number of elements without multiplication by element size
  [-Wmemset-elt-size]

This is indeed correct and due to a wrong usage of sizeof(). Fix that.

Cc: Stefan Weil <sw@weilnetz.de>
Cc: Leon Alrae <leon.alrae@imgtec.com>
Cc: qemu-stable@nongnu.org
LP: https://bugs.launchpad.net/qemu/+bug/1577841
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
(cherry picked from commit 9d989c732b153fe1576adbddb9879313a24d3cd2)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>