initrd: Remove erroneous comment

Most architectures have been passing the location of an initrd via the
initrd= option since their inception.  Remove the comment as it's both
wrong and unrelated to the commit that introduced it.

For a bit more context, I assume there's been some confusion between
"initrd" being a keyword in things like extlinux.conf and also that for
quite a long time now initrd information is passed via device tree and
not the command line on relevant architectures. But it's still true that
it's been a valid command line option to the kernel since the 90s. It's
just the case that in 2018 the code was consolidated from under arch/
and in to this file.

 [ bp: Move the context clarification up into the commit message proper. ]

Fixes: 694cfd87 ("x86/setup: Add an initrdmem= option to specify initrd physical address")
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200619143056.24538-1-trini@konsulko.com

init/do_mounts_initrd.c

@@ -45,11 +45,6 @@ static int __init early_initrdmem(char *p)
 }
 early_param("initrdmem", early_initrdmem);
 
-/*
- * This is here as the initrd keyword has been in use since 11/2018
- * on ARM, PowerPC, and MIPS.
- * It should not be; it is reserved for bootloaders.
- */
 static int __init early_initrd(char *p)
 {
 	return early_initrdmem(p);