Staging: fbtft: Fix Sparse warnings

This fixes the folowing sparse warnings:

fb_hx8340bn.c:111:6: warning: symbol 'set_addr_win' was not declared. Should it be static?
fbtft_device.c:32:19: warning: symbol 'spi_device' was not declared. Should it be static?
fbtft_device.c:33:24: warning: symbol 'p_device' was not declared. Should it be static?
Signed-off-by: Frederic Jacob <frederic.jacob.78@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_hx8340bn.c

@@ -108,7 +108,7 @@ static int init_display(struct fbtft_par *par)
 	return 0;
 }
 
-void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
+static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 {
 	fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
 		"%s(xs=%d, ys=%d, xe=%d, ye=%d)\n", __func__, xs, ys, xe, ye);

drivers/staging/fbtft/fbtft_device.c

@@ -29,8 +29,8 @@
 
 #define MAX_GPIOS 32
 
-struct spi_device *spi_device;
-struct platform_device *p_device;
+static struct spi_device *spi_device;
+static struct platform_device *p_device;
 
 static char *name;
 module_param(name, charp, 0);