Blackfin: unify u-boot linker scripts

All the Blackfin linker scripts were duplicated across the board dirs with
no difference save from the semi-often used ENV_IS_EMBEDDED option.  So
unify all of them in the lib_blackfin/ dir and for the few boards that
need to embedded the environment directly, add a LDS_BOARD_TEXT define for
them to customize via their board config file.  This is much simpler than
forcing them to duplicate the rest of the linker script.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/Makefile b/Makefile
index 84d10fa..acec1a0 100644
--- a/Makefile
+++ b/Makefile
@@ -3571,11 +3571,7 @@
 	       $(obj)board/netstar/{eeprom,crcek,crcit,*.srec,*.bin}	  \
 	       $(obj)board/trab/trab_fkt   $(obj)board/voiceblue/eeprom   \
 	       $(obj)board/armltd/{integratorap,integratorcp}/u-boot.lds  \
-	       $(obj)board/bf5{18f,26,27,33,38f,48,61}-ez{brd,kit}/u-boot.lds \
-	       $(obj)board/bf5{33,37}-stamp/u-boot.lds			  \
-	       $(obj)board/{bf537-{minotaur,pnav,srv1},blackstamp}/u-boot.lds \
-	       $(obj)board/{,t}cm-bf5{27,33,37e,48,61}/u-boot.lds	  \
-	       $(obj)board/ibf-dsp561/u-boot.lds			  \
+	       $(obj)lib_blackfin/u-boot.lds				  \
 	       $(obj)cpu/blackfin/bootrom-asm-offsets.[chs]
 	@rm -f $(obj)include/bmp_logo.h
 	@rm -f $(obj)nand_spl/{u-boot-spl,u-boot-spl.map,System.map}