efivarfs: Move to fs/efivarfs

Now that efivarfs uses the efivar API, move it out of efivars.c and
into fs/efivarfs where it belongs. This move will eventually allow us
to enable the efivarfs code without having to also enable
CONFIG_EFI_VARS built, and vice versa.

Furthermore, things like,

    mount -t efivarfs none /sys/firmware/efi/efivars

will now work if efivarfs is built as a module without requiring the
use of MODULE_ALIAS(), which would have been necessary when the
efivarfs code was part of efivars.c.

Cc: Matthew Garrett <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Reviewed-by: Tom Gundersen <[email protected]>
Tested-by: Tom Gundersen <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>

MAINTAINERS

@@ -2990,6 +2990,15 @@ F:	arch/x86/platform/efi/*
 F:	drivers/firmware/efivars.c
 F:	include/linux/efi*.h
 
+EFI VARIABLE FILESYSTEM
+M:	Matthew Garrett <[email protected]>
+M:	Jeremy Kerr <[email protected]>
+M:	Matt Fleming <[email protected]>
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git
+L:	[email protected]
+S:	Maintained
+F:	fs/efivarfs/
+
 EFIFB FRAMEBUFFER DRIVER
 L:	[email protected]
 M:	Peter Jones <[email protected]>