avr32: clean up linker script using standard macros.

As a side effect, this patch changes the .init.ramfs data to be
PAGE_SIZE-aligned, instead of 32-byte aligned.  Also, the init data is
moved into its own output sections rather than the .init output
section.

There should be no other changes to the resulting vmlinux as a result
of this patch.

Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>