Move i386 part of core.c to x86/core.c.

Separate i386 architecture specific from core.c and move it to
x86/core.c and add x86/lguest.h header file to match.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/Makefile b/drivers/lguest/Makefile
index a4567c9..d330f5b 100644
--- a/drivers/lguest/Makefile
+++ b/drivers/lguest/Makefile
@@ -6,7 +6,7 @@
 lg-y = core.o hypercalls.o page_tables.o interrupts_and_traps.o \
 	segments.o io.o lguest_user.o
 
-lg-$(CONFIG_X86_32) += x86/switcher_32.o
+lg-$(CONFIG_X86_32) += x86/switcher_32.o x86/core.o
 
 Preparation Preparation!: PREFIX=P
 Guest: PREFIX=G