lib/vdso: Remove VDSO_HAS_32BIT_FALLBACK

VDSO_HAS_32BIT_FALLBACK was introduced to address a regression which
caused seccomp to deny access to the applications to clock_gettime64()
and clock_getres64() because they are not enabled in the existing
filters.

The purpose of VDSO_HAS_32BIT_FALLBACK was to simplify the conditional
implementation of __cvdso_clock_get*time32() variants.

Now that all the architectures that support the generic vDSO library
have been converted to support the 32 bit fallbacks the conditional
can be removed.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20190830135902.20861-5-vincenzo.frascino@arm.com

References: c60a32ea ("lib/vdso/32: Provide legacy syscall fallbacks")

lib/vdso/gettimeofday.c

@@ -126,13 +126,8 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
 
 	ret = __cvdso_clock_gettime_common(clock, &ts);
 
-#ifdef VDSO_HAS_32BIT_FALLBACK
 	if (unlikely(ret))
 		return clock_gettime32_fallback(clock, res);
-#else
-	if (unlikely(ret))
-		ret = clock_gettime_fallback(clock, &ts);
-#endif
 
 	if (likely(!ret)) {
 		res->tv_sec = ts.tv_sec;
@@ -242,13 +237,8 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
 
 	ret = __cvdso_clock_getres_common(clock, &ts);
 
-#ifdef VDSO_HAS_32BIT_FALLBACK
 	if (unlikely(ret))
 		return clock_getres32_fallback(clock, res);
-#else
-	if (unlikely(ret))
-		ret = clock_getres_fallback(clock, &ts);
-#endif
 
 	if (likely(!ret && res)) {
 		res->tv_sec = ts.tv_sec;