b43: drop Kconfig option of forcing PIO mode

We have module param called use_pio which is much easier to use.

Cc: Larry Finger <larry.finger@lwfinger.net>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 0628901..d2b1d1f 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -107,7 +107,7 @@
 module_param_named(verbose, b43_modparam_verbose, int, 0644);
 MODULE_PARM_DESC(verbose, "Log message verbosity: 0=error, 1=warn, 2=info(default), 3=debug");
 
-static int b43_modparam_pio = B43_PIO_DEFAULT;
+static int b43_modparam_pio = 0;
 module_param_named(pio, b43_modparam_pio, int, 0644);
 MODULE_PARM_DESC(pio, "Use PIO accesses by default: 0=DMA, 1=PIO");