net: smc91x: Fix build without gpiolib

If GPIOLIB=n the following build errors occur:

drivers/net/ethernet/smsc/smc91x.c: In function 'try_toggle_control_gpio':
drivers/net/ethernet/smsc/smc91x.c:2204:2: error: implicit declaration of function 'devm_gpiod_get_index' [-Werror=implicit-function-declaration]
drivers/net/ethernet/smsc/smc91x.c:2204:7: warning: assignment makes pointer from integer without a cast [enabled by default]
drivers/net/ethernet/smsc/smc91x.c:2213:2: error: implicit declaration of function 'gpiod_direction_output' [-Werror=implicit-function-declaration]
drivers/net/ethernet/smsc/smc91x.c:2216:3: error: implicit declaration of function 'devm_gpiod_put' [-Werror=implicit-function-declaration]
drivers/net/ethernet/smsc/smc91x.c:2222:2: error: implicit declaration of function 'gpiod_set_value_cansleep' [-Werror=implicit-function-declaration]

Fix this by letting the driver depend on GPIOLIB if OF is selected.

Fixes: 7d2911c4 ("net: smc91x: Fix gpios for device tree based booting")
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/smsc/Kconfig

@@ -39,7 +39,7 @@ config SMC91X
 	select CRC32
 	select MII
 	depends on (ARM || M32R || SUPERH || MIPS || BLACKFIN || \
-		    MN10300 || COLDFIRE || ARM64 || XTENSA || NIOS2)
+		    MN10300 || COLDFIRE || ARM64 || XTENSA || NIOS2) && (!OF || GPIOLIB)
 	---help---
 	  This is a driver for SMC's 91x series of Ethernet chipsets,
 	  including the SMC91C94 and the SMC91C111. Say Y if you want it