Blackfin: bf527-sdp: update custom CFLAGS paths

Looks like the filesystem shuffling missed the SDP board.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

board/bf527-sdp/config.mk

@@ -23,8 +23,8 @@
 # MA 02111-1307 USA
 #
 
-CFLAGS_lib_generic += -O2
-CFLAGS_lzma += -O2
+CFLAGS_lib += -O2
+CFLAGS_lib/lzma += -O2
 
 # Set some default LDR flags based on boot mode.
 LDR_FLAGS-BFIN_BOOT_PARA := --bits 16 --dma 6