phnt mmapi fixes and improvements

[RatinCN]

• Nt(Read/Write)VirtualMemory:
  • Rename BufferSize to NumberOfBytesTo(Read/Write), this value can be smaller than the actual size of buffer.
  • Improve SAL, _Out_writes_bytes_ -> _Out_writes_bytes_to_, which implicits the real number of bytes written.
  • Improve SAL, BaseAddress cannot be NULL (same as (Read/Write)ProcessMemory).
• NtWow64XxxVirtualMemory64:
  • Type of BaseAddress should be ULONGLONG, represents a 64-bit address.
• NtWow64ReadVirtualMemory64:
  • Fix declaration, it's similar to NtReadVirtualMemory so has no Flags parameter like NtReadVirtualMemoryEx.
• NtAllocateUserPhysicalPagesEx: Fix SAL.