gcc: update *LIBC_* linker relocation reglex

gcc: update *LIBC_* linker relocation reglex

* GLIBC_DYNAMIC_LINKER64 reglex does not work for rs6000/linux64.h,
  update it.
* it turns out that UCLIBC_DYNAMIC_LINKER reglex will strip the 32/64
  chars from UCLIBC_DYNAMIC_LINKER64/UCLIBC_DYNAMIC_LINKER32, add '\b'.
  my two PCs: Centos 6.5 (python 2.7.5) and Fedora 13 (python 2.7.3)

(From OE-Core rev: a0b408191d64804df1748163060313af31433ac8)

Signed-off-by: Ting Liu <ting.liu@freescale.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>