x86/entry: Cleanup PARAVIRT

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2090231



commit 6cf3e4c0
Author: Peter Zijlstra <peterz@infradead.org>
Date:   Tue, 8 Mar 2022 16:30:21 +0100

    x86/entry: Cleanup PARAVIRT

    Since commit 5c8f6a2e ("x86/xen: Add
    xenpv_restore_regs_and_return_to_usermode()") Xen will no longer reach
    this code and we can do away with the paravirt
    SWAPGS/INTERRUPT_RETURN.

Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
    Link: https://lore.kernel.org/r/20220308154317.756014488@infradead.org



Signed-off-by: Waiman Long <longman@redhat.com>