staging: wilc1000: remove PANDA_BOARD

This patch removes one of the platform dependencies, PANDA_BOARD from the
driver codes. The device tree will provide the platform dependencies in
the future commits.

Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>