staging: comedi: ni_tio: fix warnings of uninitialized variables

Fix the following warnings by initializing these variables
to zero and add error check to return early when the check
returns an error.

drivers/staging/comedi/drivers/ni_tio.c: In function ‘ni_tio_set_sync_mode’:
drivers/staging/comedi/drivers/ni_tio.c:492:28: warning: ‘ps’ may be used uninitialized in this function [-Wuninitialized]
drivers/staging/comedi/drivers/ni_tio.c: In function ‘ni_tio_insn_config’:
drivers/staging/comedi/drivers/ni_tio.c:820:2: warning: ‘temp64’ may be used uninitialized in this function [-Wuninitialized]
drivers/staging/comedi/drivers/ni_tio.c:811:6: note: ‘temp64’ was declared her

Signed-off-by: Ted Chen <tedc.37zngo@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_tio.c

@@ -451,8 +451,9 @@ static void ni_tio_set_sync_mode(struct ni_gpct *counter)
 	unsigned int bits = 0;
 	unsigned int reg;
 	unsigned int mode;
-	unsigned int clk_src;
-	u64 ps;
+	unsigned int clk_src = 0;
+	u64 ps = 0;
+	int ret;
 	bool force_alt_sync;
 
 	/* only m series and 660x variants have counting mode registers */
@@ -482,9 +483,12 @@ static void ni_tio_set_sync_mode(struct ni_gpct *counter)
 		break;
 	}
 
-	ni_tio_generic_clock_src_select(counter, &clk_src);
-	ni_tio_clock_period_ps(counter, clk_src, &ps);
-
+	ret = ni_tio_generic_clock_src_select(counter, &clk_src);
+	if (ret)
+		return;
+	ret = ni_tio_clock_period_ps(counter, clk_src, &ps);
+	if (ret)
+		return;
 	/*
 	 * It's not clear what we should do if clock_period is unknown, so we
 	 * are not using the alt sync bit in that case.
@@ -808,7 +812,7 @@ static int ni_tio_get_clock_src(struct ni_gpct *counter,
 				unsigned int *clock_source,
 				unsigned int *period_ns)
 {
-	u64 temp64;
+	u64 temp64 = 0;
 	int ret;
 
 	ret = ni_tio_generic_clock_src_select(counter, clock_source);