lguest: use defines from x86 headers instead of magic numbers

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 9eed12d..09d9207 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -562,7 +562,7 @@
 	 * is supposed to always be "1".  Bit 9 (0x200) controls whether
 	 * interrupts are enabled.  We always leave interrupts enabled while
 	 * running the Guest. */
-	regs->eflags = 0x202;
+	regs->eflags = X86_EFLAGS_IF | 0x2;
 
 	/* The "Extended Instruction Pointer" register says where the Guest is
 	 * running. */