mips: Move initrd_start check after initrd address sanitisation.

PAGE_OFFSET is technically a virtual address so when checking the value of
initrd_start against it we should make sure that it has been sanitised from
the values passed by the bootloader. Without this change, even with a bootloader
that passes correct addresses for an initrd, we are failing to load it on MT7621
boards, for example.
Signed-off-by: Liviu Dudau <liviu@dudau.co.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/kernel/setup.c

@@ -158,10 +158,6 @@ static unsigned long __init init_initrd(void)
 		pr_err("initrd start must be page aligned\n");
 		goto disable;
 	}
-	if (initrd_start < PAGE_OFFSET) {
-		pr_err("initrd start < PAGE_OFFSET\n");
-		goto disable;
-	}
 
 	/*
 	 * Sanitize initrd addresses. For example firmware
@@ -174,6 +170,11 @@ static unsigned long __init init_initrd(void)
 	initrd_end = (unsigned long)__va(end);
 	initrd_start = (unsigned long)__va(__pa(initrd_start));
 
+	if (initrd_start < PAGE_OFFSET) {
+		pr_err("initrd start < PAGE_OFFSET\n");
+		goto disable;
+	}
+
 	ROOT_DEV = Root_RAM0;
 	return PFN_UP(end);
 disable: