x86/vdso: Drop pointless #ifdeffery in vvar_vclock_fault()

x86/vdso: Drop pointless #ifdeffery in vvar_vclock_fault()

Sparse complains rightfully when CONFIG_PARAVIRT_CLOCK and
CONFIG_HYPERV_TIMER are both not set:

  arch/x86/entry/vdso/vma.c:94:9: warning: switch with no cases

The #ifdeffery is not actually necessary as the compiler can optimize away
the branches already if these config options are not set.

Remove the #ifdeffery to make the code simpler and Sparse happy.

Closes: https://lore.kernel.org/lkml/20260117215542.405790227@kernel.org/
Reported-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://patch.msgid.link/20260331-vdso-x86-ifdef-v1-1-6be9a58b1e7e@linutronix.de