base-files: sysupgrade: correct command help text

Commit 30f61a34b4 claimed to drop -d & -p
options. In reality only -d was dropped.  Update command help text to
reflect that -d is no longer a supported option.

Fixes FS#1187

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

package/base-files/Makefile

@@ -12,7 +12,7 @@ include $(INCLUDE_DIR)/version.mk
 include $(INCLUDE_DIR)/feeds.mk
 
 PKG_NAME:=base-files
-PKG_RELEASE:=182
+PKG_RELEASE:=183
 PKG_FLAGS:=nonshared
 
 PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/

package/base-files/files/sbin/sysupgrade

@@ -55,7 +55,6 @@ Usage: $0 [<upgrade-option>...] <image file or URL>
        $0 [-q] [-i] <backup-command> <file>
 
 upgrade-option:
-	-d <delay>   add a delay before rebooting
 	-f <config>  restore configuration from .tar.gz (file or url)
 	-i           interactive mode
 	-c           attempt to preserve all changed files in /etc/