lib/util.h: use types compatible with DWORD

lib/util.h: use types compatible with DWORD

_BitScanForward() and friends are part of the Windows API and
take DWORD as parameter type. DWORD is defined to be 'unsigned long'
in Windows' header files.

We call into these functions from within lib/util.h. Currently, we
pass arguments of type uint32_t which is type defined to
'unsigned int'. This incompatiblity causes failures when we compile
the code as C++ code or with warnings enabled, when compiled as C
code.

The fix is to use 'unsigned long' rather than fixed size type.

Co-Authored-by: Linda Sun <lsun@vmware.com>
Signed-off-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Linda Sun <lsun@vmware.com>
Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>