nios2: Fix update_mmu_cache preload the TLB with the new PTE

There is a bug in the TLB preload caused by the pid not being
shifted to the correct location in tlbmisc register.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>