s390/protvirt: fix compilation issue

The kernel fails to compile with CONFIG_PROTECTED_VIRTUALIZATION_GUEST
set but CONFIG_KVM unset.

This patch fixes the issue by making the needed variable always available.

Link: https://lkml.kernel.org/r/20200423120114.2027410-1-imbrenda@linux.ibm.com
Fixes: a0f60f8 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Philipp Rudo <prudo@linux.ibm.com>
Suggested-by: Philipp Rudo <prudo@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: Claudio Imbrenda

arch/s390/boot/uv.c

@@ -7,9 +7,7 @@
 #ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 int __bootdata_preserved(prot_virt_guest);
 #endif
-#if IS_ENABLED(CONFIG_KVM)
 struct uv_info __bootdata_preserved(uv_info);
-#endif
 
 void uv_query_info(void)
 {

arch/s390/kernel/uv.c

@@ -23,10 +23,11 @@
 int __bootdata_preserved(prot_virt_guest);
 #endif
 
+struct uv_info __bootdata_preserved(uv_info);
+
 #if IS_ENABLED(CONFIG_KVM)
 int prot_virt_host;
 EXPORT_SYMBOL(prot_virt_host);
-struct uv_info __bootdata_preserved(uv_info);
 EXPORT_SYMBOL(uv_info);
 
 static int __init prot_virt_setup(char *val)