- fix WRITE_RPS0 and WRITE_RPS1 inlines, fix usage in mxb and budget
   drivers
 - export "saa7146_start_preview" and "saa7146_stop_preview" to allow
   drivers to start and stop video overlay (necessary for analog module
   support in the av7110 driver)
 - fix i2c implementation: some frontend drivers transfer a huge amount
   of firmware data (> 30kB), speed up the transmission by busy waiting
   between byte transfers for bigger transmissions
 - change ioctl function in various driver to accept a saa7146
   filehandle instead of a saa714 device structure