motu: The G1 configuration register only needs to be read when a G1 interface (aka 828mk1) is in use.  Although it's harmless for non-828mk1 interfaces, move the read into the 828mk1-specific code path to keep things neat.

git-svn-id: http://subversion.ffado.org/ffado/trunk/libffado@2497 2be59082-3212-0410-8809-b0798e1608f0
motu: fix the G1 (828mk1) register value used to represent the ADAT-optical clock source and adjust the G1 clock source mask accordingly.  Looking back at my original protocol analysis I have no idea how I arrived at a value of 0x26 for the ADAT-optical source.  When using the 828mk1, the resulting erroneous mask caused the rate to be reset to 44.1 kHz whenever the clock source was changed.  It also prevented ffado-mixer from identifying the clock source if the rate was set to 48 kHz.

git-svn-id: http://subversion.ffado.org/ffado/trunk/libffado@2498 2be59082-3212-0410-8809-b0798e1608f0