[PATCH} PPC fix td_thr_get_addr for TLS

[Roland McGrath]

> For PPC, DTPREL relocations are pre biased by the linker -0x8000
> (-TLS_DTV_OFFSET). So the TLS block addresses from the DTV must be post
> biased +0x8000 to get the correct address.

I don't understand this.  The debugger doesn't care about relocs.  It uses
the values for the TLS symbols from the ELF symbol table.  The OFFSET value
passed to td_thr_tls_get_addr comes from there.  That does not include the
bias, does it?