common: asm/desc.h is an x86-only header

From briefly going over 9062553a0d it looks like the #include in what
was ac_timer.c was added there for no reason. It's unneeded now in any
event, and it is the sole reason for Arm to have that dummy header.
Purge that, thus avoiding PPC (and later RISC-V) to also gain one.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>

xen/arch/arm/include/asm/desc.h

@@ -1,12 +0,0 @@
-#ifndef __ARCH_DESC_H
-#define __ARCH_DESC_H
-
-#endif /* __ARCH_DESC_H */
-/*
- * Local variables:
- * mode: C
- * c-file-style: "BSD"
- * c-basic-offset: 4
- * indent-tabs-mode: nil
- * End:
- */

xen/common/timer.c

@@ -22,7 +22,6 @@
 #include <xen/rcupdate.h>
 #include <xen/symbols.h>
 #include <asm/system.h>
-#include <asm/desc.h>
 #include <asm/atomic.h>
 
 /* We program the time hardware this far behind the closest deadline. */