Transmit gain can't be adjusted because sign of value sent is wrong

[kantooon]

Pluto expects gain to be a negative number between -89 and 0. Currently gain can't be adjusted so I created pull request #4 which contains this fix.

[nsdoukos]

Hello. I am using SoapyPlutoSDR for a grc block and i use positive gain numbers and work as expected for both the TX and RX. What problem are you experiencing exactly? Was the problem in the libiio or the libad9361 and it is fixed also for you?

[kantooon]

@nsdoukos the Pothosware fork of this repo already contains this fix, pull request left here as courtesy to author.