arch: Move initrd= parsing into do_mounts_initrd.c

ARC, ARM, ARM64 and Unicore32 are all capable of parsing the "initrd="
command line parameter to allow specifying the physical address and size
of an initrd. Move that parsing into init/do_mounts_initrd.c such that
we no longer duplicate that logic.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

arch/arm/mm/init.c

@@ -51,23 +51,6 @@ unsigned long __init __clear_cr(unsigned long mask)
 #endif
 
 #ifdef CONFIG_BLK_DEV_INITRD
-static int __init early_initrd(char *p)
-{
-	phys_addr_t start;
-	unsigned long size;
-	char *endp;
-
-	start = memparse(p, &endp);
-	if (*endp == ',') {
-		size = memparse(endp + 1, NULL);
-
-		phys_initrd_start = start;
-		phys_initrd_size = size;
-	}
-	return 0;
-}
-early_param("initrd", early_initrd);
-
 static int __init parse_tag_initrd(const struct tag *tag)
 {
 	pr_warn("ATAG_INITRD is deprecated; "