drivers/pinmux: Change spaces by tabs in the pinmap table

Change spaces by tabulators in the Arduino 101 pinmap table.

Add comment for spi master 1 pin connection.
Jira: ZEP-518

Change-Id: Iba2e807b315c3d1b70eceddd1c6709f5a5866cba
Signed-off-by: Flavio Santes <flavio.santes@intel.com>
Signed-off-by: Baohong Liu <baohong.liu@intel.com>