powerpc/pseries: Move plpks.h to include directory

Move plpks.h from platforms/pseries/ to include/asm/. This is necessary
for later patches to make use of the PLPKS from code in other subsystems.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230210080401.345462-15-ajd@linux.ibm.com

arch/powerpc/include/asm/plpks.h

@@ -6,8 +6,10 @@
  * Platform keystore for pseries LPAR(PLPKS).
  */
 
-#ifndef _PSERIES_PLPKS_H
-#define _PSERIES_PLPKS_H
+#ifndef _ASM_POWERPC_PLPKS_H
+#define _ASM_POWERPC_PLPKS_H
+
+#ifdef CONFIG_PSERIES_PLPKS
 
 #include <linux/types.h>
 #include <linux/list.h>
@@ -68,4 +70,6 @@ int plpks_read_fw_var(struct plpks_var *var);
  */
 int plpks_read_bootloader_var(struct plpks_var *var);
 
-#endif
+#endif // CONFIG_PSERIES_PLPKS
+
+#endif // _ASM_POWERPC_PLPKS_H

arch/powerpc/platforms/pseries/plpks.c

@@ -18,8 +18,7 @@
 #include <linux/types.h>
 #include <asm/hvcall.h>
 #include <asm/machdep.h>
-
-#include "plpks.h"
+#include <asm/plpks.h>
 
 #define PKS_FW_OWNER	     0x1
 #define PKS_BOOTLOADER_OWNER 0x2