UML: change sigcontext fields to match x86

git-x86, in commit 70aa1bd3839e3ec74ce65316528a82570e8de666, changed
a lot of the sigcontext field names.  This patch changes UML usage to
match.

I also changed includes of generic headers from "" to <>.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>