Revert "module: Add retpoline tag to VERMAGIC"

BugLink: https://bugs.launchpad.net/bugs/1820872

This reverts commit 6cfb521a.

Turns out distros do not want to make retpoline as part of their "ABI",
so this patch should not have been merged.  Sorry Andi, this was my
fault, I suggested it when your original patch was the "correct" way of
doing this instead.
Reported-by: Jiri Kosina <jikos@kernel.org>
Fixes: 6cfb521a ("module: Add retpoline tag to VERMAGIC")
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: rusty@rustcorp.com.au
Cc: arjan.van.de.ven@intel.com
Cc: jeyu@kernel.org
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(backported from commit 5132ede0)
[juergh: Adjusted context.]
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

include/linux/vermagic.h

@@ -24,16 +24,10 @@
 #ifndef MODULE_ARCH_VERMAGIC
 #define MODULE_ARCH_VERMAGIC ""
 #endif
-#ifdef RETPOLINE
-#define MODULE_VERMAGIC_RETPOLINE "retpoline "
-#else
-#define MODULE_VERMAGIC_RETPOLINE ""
-#endif
 
 #define VERMAGIC_STRING 						\
 	UTS_RELEASE " "							\
 	MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT 			\
 	MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_MODVERSIONS	\
-	MODULE_ARCH_VERMAGIC						\
-	MODULE_VERMAGIC_RETPOLINE
+	MODULE_ARCH_VERMAGIC