staging: wilc1000: moves LINUX_RX_SIZE, LINUX_TX_SIZE

This patch moves LINUX_RX_SIZE and LINUX_TX_SIZE to wilc_wlan.h file
because there are only used to wilc_wlan.c file.

Signed-off-by: Chris Park <chris.park@atmel.com>
Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>