Rename CONFIG_SYS_AUTOLAOD to CONFIG_SYS_DISABLE_AUTOLOAD

The "autoload" environment variable is always checked with env_get_yesno
as it can be set to any form of no.  The default behavior of
env_get_yesno is to return -1 on variables that are not set, which acts
as true in general (we test for non-zero return).  To convert
CONFIG_SYS_AUTOLOAD to Kconfig, given that it was almost always used to
set autoload to no, first rename to CONFIG_SYS_DISABLE_AUTOLOAD for
consistency sake.  Then, make it so that if enabled we set autoload=0 in
the default environment.  Migrate all platforms which set
CONFIG_SYS_AUTOLOAD to non-true or that set autoload to false in their
default environment to using CONFIG_SYS_DISABLE_AUTOLOAD

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/nas220.h b/include/configs/nas220.h
index 815f81f..a8a905d 100644
--- a/include/configs/nas220.h
+++ b/include/configs/nas220.h
@@ -42,8 +42,7 @@
 	"0x500000@0xc0000(uimage),"\
 	"0x1a40000@0x5c0000(rootfs)\0" \
 	"mtdids=nand0=orion_nand\0"\
-	"autostart=no\0"\
-	"autoload=no\0"
+	"autostart=no\0"
 
 /*
  * Ethernet Driver configuration