pinctrl: tegra: use signed bitfields for optional fields

Optional fields are set to -1 by various preprocessor macros. Make
sure the fields can actually store them.

Signed-off-by: Stefan Agner <[e-mail]>
Acked-by: Stephen Warren <[e-mail]>
Tested-by: Stephen Warren <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/pinctrl-tegra.h

···
 	u32 pupd_bank:2;
 	u32 tri_bank:2;
 	u32 drv_bank:2;
-	u32 mux_bit:6;
-	u32 pupd_bit:6;
-	u32 tri_bit:6;
-	u32 einput_bit:6;
-	u32 odrain_bit:6;
-	u32 lock_bit:6;
-	u32 ioreset_bit:6;
-	u32 rcv_sel_bit:6;
-	u32 hsm_bit:6;
-	u32 schmitt_bit:6;
-	u32 lpmd_bit:6;
-	u32 drvdn_bit:6;
-	u32 drvup_bit:6;
-	u32 slwr_bit:6;
-	u32 slwf_bit:6;
-	u32 drvtype_bit:6;
-	u32 drvdn_width:6;
-	u32 drvup_width:6;
-	u32 slwr_width:6;
-	u32 slwf_width:6;
+	s32 mux_bit:6;
+	s32 pupd_bit:6;
+	s32 tri_bit:6;
+	s32 einput_bit:6;
+	s32 odrain_bit:6;
+	s32 lock_bit:6;
+	s32 ioreset_bit:6;
+	s32 rcv_sel_bit:6;
+	s32 hsm_bit:6;
+	s32 schmitt_bit:6;
+	s32 lpmd_bit:6;
+	s32 drvdn_bit:6;
+	s32 drvup_bit:6;
+	s32 slwr_bit:6;
+	s32 slwf_bit:6;
+	s32 drvtype_bit:6;
+	s32 drvdn_width:6;
+	s32 drvup_width:6;
+	s32 slwr_width:6;
+	s32 slwf_width:6;
 };
 
 /**