net: Fix discuss discard typo

Replace discuss with discard, that is what happens with packet with
incorrect checksum. Fix the typo.

Fixes: 4b37fd146bb ("Convert CONFIG_UDP_CHECKSUM to Kconfig")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Ramon Fried <rfried.dev@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
diff --git a/net/Kconfig b/net/Kconfig
index 964a4fe..564ea8b 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -158,7 +158,7 @@
 	default y if SANDBOX
 	help
 	  Enable this to verify the checksum on UDP packets. If the checksum
-	  is wrong then the packet is discussed and an error is shown, like
+	  is wrong then the packet is discarded and an error is shown, like
 	  "UDP wrong checksum 29374a23 30ff3826"
 
 config BOOTP_SERVERIP