x86/paravirt: Move pv_native_*() prototypes to paravirt.c

x86/paravirt: Move pv_native_*() prototypes to paravirt.c

The only reason the pv_native_*() prototypes are needed is the complete
definition of those functions via an asm() statement, which makes it
impossible to have those functions as static ones.

Move the prototypes from paravirt_types.h into paravirt.c, which is the
only source referencing the functions.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260105110520.21356-15-jgross@suse.com