linker: Modify linker scripts to be more generic

Make use of "IMAGE_MAX_SIZE" and "IMAGE_TEXT_BASE" rather than
CONFIG_SPL_MAX_SIZE and CONFIG_SPL_TEXT_BASE.  This lets us re-use the
same script for both SPL and TPL.  Add logic to scripts/Makefile.spl to
pass in the right value when preprocessing the script.

Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Jagan Teki <jagan@openedev.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Andreas Bießmann <andreas@biessmann.org>
Cc: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: York Sun <york.sun@nxp.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Adam Ford <aford173@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Tested-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Tested-by: Adam Ford <aford173@gmail.com> #da850evm & omap3_logic_somlv
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

arch/powerpc/cpu/mpc85xx/u-boot-spl.lds

@@ -18,11 +18,7 @@ PHDRS
 #endif
 SECTIONS
 {
-#ifdef CONFIG_TPL_BUILD
-	. = CONFIG_TPL_TEXT_BASE;
-#else
-	. = CONFIG_SPL_TEXT_BASE;
-#endif
+	. = IMAGE_TEXT_BASE;
 	.text : {
 		*(.text*)
 	}