drivers: input: touchscreen: add gslx6801 driver.

This driver is for the new rk3368 evb board.
static global variable,solve compilation problems.
There are two ways to speed up system startup:
  a.replace msleep() with usleep_range().
  b.enable asynchronous probing.
Modify delay time.

- modify GSLX680_I2C_NAME:
    before: gslx680 driver and gslx6801 driver have the same name,
            causing the kernel to register gslx680 driver failed.
- add power control:
    in gsl_ts_probe() enable power; in gsl_ts_remove disable power.
- fix for none pinctrl
- fix gslX680_ts_worker() error: buffer overflow 'key_x' 512 <= 512

Change-Id: I7d7ae9879397d1850e5cd1092fb2730f6d1fdf18
Signed-off-by: Wang Jie <dave.wang@rock-chips.com>
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>

drivers/input/touchscreen/Kconfig

@@ -399,6 +399,11 @@ config TOUCHSCREEN_GOODIX
 	  To compile this driver as a module, choose M here: the
 	  module will be called goodix.
 
+config TOUCHSCREEN_GSLX6801
+	tristate "gslx 6801"
+	help
+	  gslX6801 touchpad driver for pad
+
 config TOUCHSCREEN_GSLX680A
         tristate "gslx 680a"
         help

drivers/input/touchscreen/Makefile

@@ -45,6 +45,7 @@ obj-$(CONFIG_TOUCHSCREEN_EGALAX_SERIAL)	+= egalax_ts_serial.o
 obj-$(CONFIG_TOUCHSCREEN_EXC3000)	+= exc3000.o
 obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix.o
+obj-$(CONFIG_TOUCHSCREEN_GSLX6801)      += gslx6801.o gsl_point_id.o
 obj-$(CONFIG_TOUCHSCREEN_GSLX680A)      += gslx680a.o gsl_point_id.o
 obj-$(CONFIG_TOUCHSCREEN_GSLX680_D708)	+= gslx680_d708/ gsl_point_id.o
 obj-$(CONFIG_TOUCHSCREEN_GSLX680_PAD)	+= gslx680_pad.o gsl_point_id.o