kwbimage: Rename CONFIG_SYS_SPI_U_BOOT_OFFS to CONFIG_SYS_U_BOOT_OFFS

To use this offset for other boot device (like SDIO/MMC), lets rename
it to a more generic name. This will be used be the SDIO/MMC SPL boot
support for the A38x.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Cc: Dirk Eibach <eibach@gdsys.de>
diff --git a/tools/kwbimage.c b/tools/kwbimage.c
index 91e0990..3fa90d3 100644
--- a/tools/kwbimage.c
+++ b/tools/kwbimage.c
@@ -421,15 +421,15 @@
 			*hasext = 1;
 	}
 
-#if defined(CONFIG_SYS_SPI_U_BOOT_OFFS)
-	if (headersz > CONFIG_SYS_SPI_U_BOOT_OFFS) {
+#if defined(CONFIG_SYS_U_BOOT_OFFS)
+	if (headersz > CONFIG_SYS_U_BOOT_OFFS) {
 		fprintf(stderr, "Error: Image header (incl. SPL image) too big!\n");
-		fprintf(stderr, "header=0x%x CONFIG_SYS_SPI_U_BOOT_OFFS=0x%x!\n",
-			(int)headersz, CONFIG_SYS_SPI_U_BOOT_OFFS);
-		fprintf(stderr, "Increase CONFIG_SYS_SPI_U_BOOT_OFFS!\n");
+		fprintf(stderr, "header=0x%x CONFIG_SYS_U_BOOT_OFFS=0x%x!\n",
+			(int)headersz, CONFIG_SYS_U_BOOT_OFFS);
+		fprintf(stderr, "Increase CONFIG_SYS_U_BOOT_OFFS!\n");
 		return 0;
 	} else {
-		headersz = CONFIG_SYS_SPI_U_BOOT_OFFS;
+		headersz = CONFIG_SYS_U_BOOT_OFFS;
 	}
 #endif