staging: wilc1000: remove firmware definition

This patch removes the firmware definitions, STA_FIRMWARE, AP_FIRMWARE, and
P2P_CONCURRENCY_FIRMWARE from the linux_wlan.c file because they are
defined in the Makefile.

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