zchk-time: Fix fails of sb_add_localtime_iso8601(_msec) tests.

These tests used the "Asia/Katmandu" timezone... that is apparently a
typo for "Asia/Kathmandu" (which is the correct timezone name). The
former apparently still existed for backward-compatibility reasons, but
was deprecated on some recent systems.

Fix the tests by using the correct spelling.

Change-Id: Ied2308d7712d7d6c3912b3c897b0163599d9ce06
Priv-Id: c9a6b2b7137312f259022bf8ec786867bcc8a0e5

Author: LpZ-squall

tests/zchk-time.c

@@ -352,7 +352,7 @@ Z_GROUP_EXPORT(time)
         Z_ASSERT_STREQUAL(sb.data, "2012-07-12T13:20:30+03:00");
 
         sb.len = 0;
-        sb_add_localtime_iso8601(&sb, ts, ":Asia/Katmandu");
+        sb_add_localtime_iso8601(&sb, ts, ":Asia/Kathmandu");
         Z_ASSERT_STREQUAL(sb.data, "2012-07-12T16:05:30+05:45");
 
         sb.len = 0;
@@ -382,7 +382,7 @@ Z_GROUP_EXPORT(time)
         Z_ASSERT_STREQUAL(sb.data, "2012-07-12T13:20:30.123+03:00");
 
         sb.len = 0;
-        sb_add_localtime_iso8601_msec(&sb, ts, 123, ":Asia/Katmandu");
+        sb_add_localtime_iso8601_msec(&sb, ts, 123, ":Asia/Kathmandu");
         Z_ASSERT_STREQUAL(sb.data, "2012-07-12T16:05:30.123+05:45");
 
         sb.len = 0;