[PATCH] msasn1: Add stub for ASN1_Decode function

[Vijay Kiran Kamuju]

ASN1decoding_t and ASN1encoding_t are implemented as linked lists.
Current implementation does not properly emulate the linked list, as
 we need to identify where the next link pointers are stored.

This patch adds a stub for ASN1_Decode function so that second crash
 related to the bug #38020 can be avoided and close the bug.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=38020
Signed-off-by: Vijay Kiran Kamuju <infyquest(a)gmail.com>