Cygwin: fix initializing MEM_EXTENDED_PARAMETER

Cygwin: fix initializing MEM_EXTENDED_PARAMETER

MEM_EXTENDED_PARAMETER consists of a 64 bit bitfield which contains
the Type and the Reserved members.  The former usage of designated
initializer lists initialized Type, but not Reserved.  Since that's
not possible anymore due to a g++ 11.2 bug, Cygwin initializes the
MEM_EXTENDED_PARAMETER structs explicitely.  This results in a
random value in Reserved, which at least VirtualAlloc2 chokes on
(ERROR_INVALID_PARAMETER).

Set Reserved explicitely to 0 for a fix.

Fixes: bdb7991db38b ("Cygwin: workaround a g++ 11.2 initialization bug")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>