common: update: fix an "unused" warning against update_flash()

Since update_flash() is used only in update_tftp(), it should be
guarded with appropriate config options.

After the commit 3149e524fc1e, common/update.c will be built under
either CONFIG_UDATE_TFTP, CONFIG_DFU_TFTP or CONFIG_UPDATE_FIT.
Since CONFIG_UPDATE_FIT, hence fit_update(), doesn't rely on
update_flash(), the compiler may cause an "unused" warning if
CONFIG_UPDATE_FIT=y and CONFIG_UPDATE_TFTP=n and CONFIG_DFU_TFTP=n.

This is, for example, the case for sandbox defconfig where
EFI_CAPSULE_FIRMWARE_FIT is enabled for test purpose.

Fixes: 3149e524fc1e ("common: update: add a generic interface for FIT
       image")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
diff --git a/common/update.c b/common/update.c
index 808be08..a5879cb 100644
--- a/common/update.c
+++ b/common/update.c
@@ -29,7 +29,7 @@
 #include <errno.h>
 #include <mtd/cfi_flash.h>
 
-#ifdef CONFIG_DFU_TFTP
+#if defined(CONFIG_DFU_TFTP) || defined(CONFIG_UPDATE_TFTP)
 /* env variable holding the location of the update file */
 #define UPDATE_FILE_ENV		"updatefile"
 
@@ -99,7 +99,6 @@
 
 	return rv;
 }
-#endif /* CONFIG_DFU_TFTP */
 
 #ifdef CONFIG_MTD_NOR_FLASH
 static int update_flash_protect(int prot, ulong addr_first, ulong addr_last)
@@ -216,6 +215,7 @@
 #endif
 	return 0;
 }
+#endif /* CONFIG_DFU_TFTP || CONFIG_UPDATE_TFTP */
 
 static int update_fit_getparams(const void *fit, int noffset, ulong *addr,
 						ulong *fladdr, ulong *size)
@@ -233,7 +233,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_DFU_TFTP
+#if defined(CONFIG_DFU_TFTP) || defined(CONFIG_UPDATE_TFTP)
 int update_tftp(ulong addr, char *interface, char *devstring)
 {
 	char *filename, *env_addr, *fit_image_name;
@@ -340,7 +340,7 @@
 
 	return ret;
 }
-#endif /* CONFIG_DFU_UPDATE */
+#endif /* CONFIG_DFU_UPDATE || CONFIG_UPDATE_TFTP */
 
 #ifdef CONFIG_UPDATE_FIT
 /**