samples/net: Remove redundant configuration variable

Remove CONFIG_GPIO=y for the Arduino 101 board. This configuration
is now set by default in the board configuration file.

See commit 8f96628064475ed34288ed0583a881835b666501.

Change-Id: I6fa73a5785d78c51f03a0af48fc2aa8cc7636c7d
Signed-off-by: Flavio Santes <flavio.santes@intel.com>
5 files changed