misc: fix ti-st build issues

st_drv uses skb*() interfaces, so it should depend on NET.
It also uses GPIO interfaces, so it should depend on GPIOLIB.

st_kim.c uses syss_*() calls, so it should #include
<linux/sysfs.h>.

Fixes these observed build errors:
ERROR: "skb_queue_purge" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "skb_pull" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "skb_queue_tail" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "__alloc_skb" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "kfree_skb" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "skb_dequeue" [drivers/misc/ti-st/st_drv.ko] undefined!
ERROR: "skb_put" [drivers/misc/ti-st/st_drv.ko] undefined!
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/misc/ti-st/Kconfig

@@ -5,6 +5,7 @@
 menu "Texas Instruments shared transport line discipline"
 config TI_ST
 	tristate "Shared transport core driver"
+	depends on NET && GPIOLIB
 	select FW_LOADER
 	help
 	  This enables the shared transport core driver for TI

drivers/misc/ti-st/st_kim.c

@@ -30,6 +30,7 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/sched.h>
+#include <linux/sysfs.h>
 #include <linux/tty.h>
 
 #include <linux/skbuff.h>