Convert cpu_write_elfXX_note() functions to CPUClass methods and pass
CPUState as argument. Update target-i386 accordingly.
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
[AF: Retain stubs as CPUClass' default method implementation; style changes]
Signed-off-by: NAndreas Färber <afaerber@suse.de>