ipw2200: Remove set but unused variables 'rc' and 'w'

ipw2200: Remove set but unused variables 'rc' and 'w'

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/intel/ipw2x00/ipw2200.c: In function ‘ipw_irq_tasklet’:
 drivers/net/wireless/intel/ipw2x00/ipw2200.c:1953:6: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]
 drivers/net/wireless/intel/ipw2x00/ipw2200.c: In function ‘ipw_rx’:
 drivers/net/wireless/intel/ipw2x00/ipw2200.c:8251:9: warning: variable ‘w’ set but not used [-Wunused-but-set-variable]

Cc: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Gerald Combs <gerald@ethereal.com>
Cc: Linux Wireless <ilw@linux.intel.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200814113933.1903438-17-lee.jones@linaro.org