gcc: Drop part of the 64bithack patch which is no longer used

gcc: Drop part of the 64bithack patch which is no longer used

Since we now handle GLIBC_DYNAMIC_LINKER in gcc-configure-common.inc:

's#\(GLIBC_DYNAMIC_LINKER[^ ]*\)\( *"/lib.*\)#\1 SYSTEMLIBS_DIR\2#'

we can drop the patch which changes a hardcoded value for this.

No PR bump since there is no code change resulting from this, its just
a cleanup.

There is still a valid question over the remainder of this patch and its
interaction with multilib configurations.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>