lib: Allow using display_buffer() in SPL

At present this function uses printf() format strings that are not
supported in SPL, so the output just consists of %llx strings on 64-bit.
machines. Fix this by adding a special case.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

lib/display_options.c

@@ -174,7 +174,9 @@ int print_buffer(ulong addr, const void *data, uint width, uint count,
 				x = lb.us[i] = *(volatile uint16_t *)data;
 			else
 				x = lb.uc[i] = *(volatile uint8_t *)data;
-#ifdef CONFIG_SYS_SUPPORT_64BIT_DATA
+#if defined(CONFIG_SPL_BUILD)
+			printf(" %x", (uint)x);
+#elif defined(CONFIG_SYS_SUPPORT_64BIT_DATA)
 			printf(" %0*llx", width * 2, (long long)x);
 #else
 			printf(" %0*x", width * 2, x);