staging: wilc1000: replace wilc error types with the generic error types

This patch replaces the error types defined by wilc driver with the
generic error types provided by the Linux kernel.
- WILC_SUCCESS			0
- WILC_FAIL				-EFAULT
- WILC_BUSY				-EBUSY
- WILC_INVALID_ARGUMENT		-EINVAL
- WILC_INVALID_STATE		-EINVAL
- WILC_BUFFER_OVERFLOW		-EOVERFLOW
- WILC_NULL_PTR			-EFAULT
- WILC_TIMEOUT			-ETIMEDOUT
- WILC_NOT_FOUND			-ENOENT
- WILC_NO_MEM			-ENOMEM

After then removes all wilc definitions.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>