crc32: Exclude crc32 from TPL

Unfortunately the toolchain often brings in the crc32 table even if the
function is not actually used. For now, exclude it from the TPL build,
which is very sensitive to size.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/Makefile

@@ -92,7 +92,9 @@ obj-y += display_options.o
 CFLAGS_display_options.o := $(if $(BUILD_TAG),-DBUILD_TAG='"$(BUILD_TAG)"')
 obj-$(CONFIG_BCH) += bch.o
 obj-$(CONFIG_MMC_SPI) += crc7.o
+#ifndef CONFIG_TPL_BUILD
 obj-y += crc32.o
+#endif
 obj-$(CONFIG_CRC32C) += crc32c.o
 obj-y += ctype.o
 obj-y += div64.o