[PATCH][PowerPC] Fix BlockAddress access on ppc64

[Anton Blanchard]

Hi Uli,

> > The attached patch fixes this by loading such values from the TOC,
> > as is done for any other global symbol.
> 
> Thanks! I verified this fixed the issue for me.

Sorry, I spoke too soon:

kernel/built-in.o:(.toc+0x0): undefined reference to `.Ltmp371608'

.Ltmp35:                                # Block address taken
# BB#1:                                 # %__here
        addis 3, 2, .LC7 at toc@ha
        li 4, 512
        ld 3, .LC7 at toc@l(3)
        bl __local_bh_enable_ip

...

.LC7:
        .tc .Ltmp3543[TC],.Ltmp3543

Anton