arm/paravirt: Use common code for paravirt_steal_clock()

arm/paravirt: Use common code for paravirt_steal_clock()

Remove the arch-specific variant of paravirt_steal_clock() and use
the common one instead.

This allows to remove paravirt.c and paravirt.h from arch/arm.

Until all archs supporting Xen have been switched to the common code
of paravirt_steal_clock(), drivers/xen/time.c needs to include
asm/paravirt.h for those archs, while this is not necessary for arm
any longer.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260105110520.21356-8-jgross@suse.com