Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/parisc/include/asm/sparsemem.h b/arch/parisc/include/asm/sparsemem.h
new file mode 100644
index 0000000..b5c3a79
--- /dev/null
+++ b/arch/parisc/include/asm/sparsemem.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ASM_PARISC_SPARSEMEM_H
+#define ASM_PARISC_SPARSEMEM_H
+
+/* We have these possible memory map layouts:
+ * Astro: 0-3.75, 67.75-68, 4-64
+ * zx1: 0-1, 257-260, 4-256
+ * Stretch (N-class): 0-2, 4-32, 34-xxx
+ */
+
+#define MAX_PHYSMEM_BITS	39	/* 512 GB */
+#define SECTION_SIZE_BITS	27	/* 128 MB */
+
+#endif