configure: Drop adjustment of textseg

configure: Drop adjustment of textseg

This adjustment was random and unnecessary.  The user mode
startup code in probe_guest_base() will choose a value for
guest_base that allows the host qemu binary to not conflict
with the guest binary.

With modern distributions, this isn't even used, as the default
is PIE, which does the same job in a more portable way.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v2: Remove mention of config-host.ld from make distclean