tda19988: add missing blockdriver_announce() call

To provide EDID to fb, the TDA19988 implements the block device
protocol with libblockdriver. To properly use the library,
blockdriver_announce() should be called by the driver.

Issue reported by David van Moolenbroek

Change-Id: Id55d159d91502a9afac5c1d4de0fee1e8945b5c1
bmp085: remove duplicate code

A copy and paste error caused a few lines of code to be duplicated.
This patch removes the excess code.

Change-Id: I7313efb537e2a4102fb25ce05782e82ae0c84285
libi2cdriver: add functions for IC register access

Many i2c device drivers used similar code to access registers on
the ICs they drive. This commit implements that functionality in
libi2cdriver and updates the drivers to use the library instead of
their own register access functions. The net result is 375+ fewer
lines of code and less work for people developing new drivers.

The two exceptions were cat24c256 and parts of tda19988. They access
the bus in uncommon ways. It doesn't make sense at this time to
move their read/write functions into libi2cdriver.

Change-Id: Id8280b71af33b710a49944d7f20a7262be9f5988
i2c: increase read/write timeout

The sht21 temperature and humidity sensor holds the i2c bus while
an ADC conversion is in progress. For example, a temperature
measurement is requested, a read operation is started, and the
sht21 doesn't respond to the read request until the result of
the measurement is ready. The conversion time isn't constant.
On rare occations (one in hundreds of samples) the timeout in the
i2c driver expires returning an error.

The example code from Sensirion, the sht21's manufacturer, suggests
a bus timeout of 1 second to accommodate the sht21. This commit
increases the bus timeout to 1 second. The timeout is only reached
when chips do not respond normally, so the change doesn't affect the
performance of any other drivers.

Change-Id: I57b0f958a5d0b69b221af380b771fe67401ff604