[PATCH] Fix mxb.c stack usage

This does the following:
 - make initialization data for helper chipsets (saa7111 and saa7740)
   static and with file scope

Additionally fixes:
 - don't use irq driven i2c transfer when saa7740 is present (this screws
   up the i2c bus and may hang the computer)
 - add MODULE_DEVICE_TABLE to allow /sbin/hotplug to handle the device