Blackfin: bf537-stamp: drop old spi_flash driver

The new common spi framework and spi flash subsystem provides all the same
functionality as the old Blackfin-specific driver, so punt the old one as
it has been sticking around long enough.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

board/bf537-stamp/Makefile

@@ -31,7 +31,6 @@ LIB	= $(obj)lib$(BOARD).a
 
 COBJS-y	:= $(BOARD).o cmd_bf537led.o
 COBJS-$(CONFIG_BFIN_IDE)   += ide-cf.o
-COBJS-$(CONFIG_CMD_EEPROM) += spi_flash.o
 COBJS-$(CONFIG_POST)       += post.o post-memory.o
 
 SRCS	:= $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c)