x86: Fix linker script

Do not load sections to specific addresses. This fixes linking which otherwise
fails with newer toolchains with:

/opt/OSELAS.Toolchain-2012.12.1/i586-unknown-linux-gnu/gcc-4.7.2-glibc-2.16.0-binutils-2.22-kernel-3.6-sanitized/bin/i586-unknown-linux-gnu-ld: section .eh_frame loaded at [0000000000015fb4,000000000001b0bf] overlaps section .barebox_initcalls loaded at [0000000000015fb4,000000000001600f]

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>