smb.c: Fixed compilation warnings

smb.c:162: error: comma at end of enumerator list
smb.c:469: warning: conversion from 'size_t' to 'unsigned short',
           possible loss of data
smb.c:517: warning: conversion from 'curl_off_t' to 'unsigned int',
           possible loss of data
smb.c:545: warning: conversion from 'curl_off_t' to 'unsigned int',
           possible loss of data