autoboot: make sure watchdog device(s) are handled with keyed autoboot

Currently, AUTOBOOT_KEYED and its variant AUTOBOOT_ENCRYPTION are
broken when one has an external always-running watchdog device with a
timeout shorter than the configured boot delay (in my case, I have a
gpio-wdt one with a timeout of 1 second), because we fail to call
WATCHDOG_RESET() in the loops where we wait for the bootdelay to
elapse.

This is done implicitly in the !AUTOBOOT_KEYED case,
i.e. abortboot_single_key(), because that loop contains a
udelay(10000), and udelay() does a WATCHDOG_RESET().

To fix this, simply add similar udelay() calls in the other loops.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/common/autoboot.c b/common/autoboot.c
index 63f2587..cdafe76 100644
--- a/common/autoboot.c
+++ b/common/autoboot.c
@@ -115,6 +115,7 @@
 				presskey_len++;
 			}
 		}
+		udelay(10000);
 	} while (never_timeout || get_ticks() <= etime);
 
 	return abort;
@@ -206,6 +207,7 @@
 			if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
 				abort = 1;
 		}
+		udelay(10000);
 	} while (!abort && get_ticks() <= etime);
 
 	free(presskey);
@@ -293,6 +295,7 @@
 				abort = 1;
 			}
 		}
+		udelay(10000);
 	} while (!abort && get_ticks() <= etime);
 
 	return abort;