Fix BUG_ON() reporting in real mode on powerpc

[Anshuman Khandual]

On 02/17/2016 12:46 PM, Balbir Singh wrote:
>> > It might be a little better to do this:
>> > 
>> > 		bugaddr = regs->nip;
>> > 		if (REGION_ID(bugaddr) == 0 && !(regs->msr & MSR_IR))
>> > 			bugaddr += PAGE_OFFSET;
>> > 
>> > It is possible to execute from addresses with the 0xc000... on top in
>> > real mode, because the CPU ignores the top 4 address bits in real
>> > mode.
> Good catch! Thank you
> 
> Changelog:
>      Don't add PAGE_OFFSET blindly, check if REGION_ID is 0

Cant we use USER_REGION_ID directly ?