MIPS: pgtable-bits: Fix XPA damage to R6 definitions.

Commit be0c37c985 ("MIPS: Rearrange PTE bits into fixed positions.")
rearranged the PTE bits into fixed positions in preparation for the XPA
support. However, this patch broke R6 since it only took R2 cores
into consideration for the RI/XI bits leading to boot failures. We fix
this by adding the missing CONFIG_CPU_MIPSR6 definitions

Fixes: be0c37c985 ("MIPS: Rearrange PTE bits into fixed positions.")
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10208/
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/pgtable-bits.h

@@ -113,7 +113,7 @@
 #define _PAGE_PRESENT_SHIFT	0
 #define _PAGE_PRESENT		(1 << _PAGE_PRESENT_SHIFT)
 /* R2 or later cores check for RI/XI support to determine _PAGE_READ */
-#ifdef CONFIG_CPU_MIPSR2
+#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 #define _PAGE_WRITE_SHIFT	(_PAGE_PRESENT_SHIFT + 1)
 #define _PAGE_WRITE		(1 << _PAGE_WRITE_SHIFT)
 #else
@@ -135,16 +135,16 @@
 #define _PAGE_SPLITTING		(1 << _PAGE_SPLITTING_SHIFT)
 
 /* Only R2 or newer cores have the XI bit */
-#ifdef CONFIG_CPU_MIPSR2
+#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 #define _PAGE_NO_EXEC_SHIFT	(_PAGE_SPLITTING_SHIFT + 1)
 #else
 #define _PAGE_GLOBAL_SHIFT	(_PAGE_SPLITTING_SHIFT + 1)
 #define _PAGE_GLOBAL		(1 << _PAGE_GLOBAL_SHIFT)
-#endif	/* CONFIG_CPU_MIPSR2 */
+#endif	/* CONFIG_CPU_MIPSR2 || CONFIG_CPU_MIPSR6 */
 
 #endif	/* CONFIG_64BIT && CONFIG_MIPS_HUGE_TLB_SUPPORT */
 
-#ifdef CONFIG_CPU_MIPSR2
+#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 /* XI - page cannot be executed */
 #ifndef _PAGE_NO_EXEC_SHIFT
 #define _PAGE_NO_EXEC_SHIFT	(_PAGE_MODIFIED_SHIFT + 1)
@@ -160,10 +160,10 @@
 #define _PAGE_GLOBAL_SHIFT	(_PAGE_NO_READ_SHIFT + 1)
 #define _PAGE_GLOBAL		(1 << _PAGE_GLOBAL_SHIFT)
 
-#else	/* !CONFIG_CPU_MIPSR2 */
+#else	/* !CONFIG_CPU_MIPSR2 && !CONFIG_CPU_MIPSR6 */
 #define _PAGE_GLOBAL_SHIFT	(_PAGE_MODIFIED_SHIFT + 1)
 #define _PAGE_GLOBAL		(1 << _PAGE_GLOBAL_SHIFT)
-#endif	/* CONFIG_CPU_MIPSR2 */
+#endif	/* CONFIG_CPU_MIPSR2 || CONFIG_CPU_MIPSR6 */
 
 #define _PAGE_VALID_SHIFT	(_PAGE_GLOBAL_SHIFT + 1)
 #define _PAGE_VALID		(1 << _PAGE_VALID_SHIFT)
@@ -205,7 +205,7 @@
  */
 static inline uint64_t pte_to_entrylo(unsigned long pte_val)
 {
-#ifdef CONFIG_CPU_MIPSR2
+#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
 	if (cpu_has_rixi) {
 		int sa;
 #ifdef CONFIG_32BIT