npcm7xx-igps: Make gBMC settings for all platforms common This makes a common set of parameters for all BMC platforms, standardizing on 25Mhz clock to the primary BMC SPI with hoth as that is the max supported frequency. Tested: Ran on AMD Rome and Intel SPR BMCs to verify that multiple BMC systems work fine with the tweaked, common settings. Google-Bug-Id: 344688999 Change-Id: Ic8f07b18d97be5ede1a57ad76178ab59dbd13a26 Signed-off-by: William A. Kennington III <wak@google.com>