target/avr32_jtag: fix error returns

Fixed only 2 error returns discovered by clang static analyzer.
There are obviously many more missing error tests in avr32_jtag.c
These was not fixed to keep this change minimal.
Not tested with hw.

Change-Id: I6c79f6248db774990ddb42c0dacdb621651ed69e
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/5378
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

src/target/avr32_jtag.c

@@ -173,19 +173,15 @@ int avr32_jtag_nexus_read(struct avr32_jtag *jtag_info,
 {
 	avr32_jtag_set_instr(jtag_info, AVR32_INST_NEXUS_ACCESS);
 	avr32_jtag_nexus_set_address(jtag_info, addr, MODE_READ);
-	avr32_jtag_nexus_read_data(jtag_info, value);
-
-	return ERROR_OK;
-
+	return avr32_jtag_nexus_read_data(jtag_info, value);
 }
+
 int avr32_jtag_nexus_write(struct avr32_jtag *jtag_info,
 		uint32_t addr, uint32_t value)
 {
 	avr32_jtag_set_instr(jtag_info, AVR32_INST_NEXUS_ACCESS);
 	avr32_jtag_nexus_set_address(jtag_info, addr, MODE_WRITE);
-	avr32_jtag_nexus_write_data(jtag_info, value);
-
-	return ERROR_OK;
+	return avr32_jtag_nexus_write_data(jtag_info, value);
 }
 
 int avr32_jtag_mwa_set_address(struct avr32_jtag *jtag_info, int slave,