Update LTC2485.cpp

[glitch911]

Fix bit operation to match datasheet description (only 6 bits are noise and should be removed, after logical shit left by one we need to remove 7 bits so /=128)

[thorenscientific]

Hi @glitch911 , thanks for pointing this out (and I note that this PR is nearly a year old.) I've got an eval board on order to dig into this, but I'm planning on refactoring the LTC2485 driver to use the LTC24XX_general library. There are 18 parts in this family, with various quirks, and differences in data output formats. The LTC24XX_general library handles these differences, and all data transfer functions return data formatted as 32-bits, consistent with the SPI devices (I2C device's data is shifted left by two bits.)
Also the LTC24XX_diff_code_to_voltage handles a bug in the 2X speedup mode, where a digital output code corresponding to exactly zero is not formatted properly.
I also see that there was never an example sketch done for this part, so I'll try to add that as well.