arm: Disable ATAGs support

With the exceptions of ds109, ds414, icnova-a20-swac, nokia_rx51 and
stemmy, disable ATAG support.  A large number of platforms had enabled
support but never supported a kernel so old as to require it.  Further,
some platforms are old enough to support both, but are well supported by
devicetree booting, and have been for a number of years.  This is
because some of the ATAGs related functions have been re-used to provide
the same kind of information, but for devicetree or just generally to
inform the user.  When needed still, rename these functions to
get_board_revision() instead, to avoid conflicts.  In other cases, these
functions were simply unused, so drop them.

Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Phil Sutter <phil@nwl.cc>
Cc: Stefan Bosch <stefan_b@posteo.net>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/mx51evk/mx51evk.c b/board/freescale/mx51evk/mx51evk.c
index c8439a6..46095ac 100644
--- a/board/freescale/mx51evk/mx51evk.c
+++ b/board/freescale/mx51evk/mx51evk.c
@@ -35,6 +35,7 @@
 	return 0;
 }
 
+#ifdef CONFIG_REVISION_TAG
 u32 get_board_rev(void)
 {
 	u32 rev = get_cpu_rev();
@@ -42,6 +43,7 @@
 		rev |= BOARD_REV_2_0 << BOARD_VER_OFFSET;
 	return rev;
 }
+#endif
 
 #define UART_PAD_CTRL	(PAD_CTL_HYS | PAD_CTL_PUS_100K_DOWN | PAD_CTL_DSE_HIGH)