flash/nor: consolidate flash protect/protect_check

Make flash_driver methods protect() and protect_check()
optional.

Remove dummy definitions of these methods from the drivers
which do not implement protection handling.

Some drivers did not define protect method. It raised segfault
before this change and now it is handled properly.

Lot of drivers returned ERROR_OK from dummy protect()
- now flash_driver_protect() returns an error if not handled by the driver.

Change-Id: I2d4a0da316bf03c6379791b1b1c6198fbf22e66c
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4765
Tested-by: jenkins
Reviewed-by: Andreas Bolsch <hyphen0break@gmail.com>
Reviewed-by: Christopher Head <chead@zaber.com>

src/flash/nor/cc26xx.c

@@ -312,12 +312,6 @@ static int cc26xx_erase(struct flash_bank *bank, int first, int last)
 	return retval;
 }
 
-static int cc26xx_protect(struct flash_bank *bank, int set, int first,
-	int last)
-{
-	return ERROR_OK;
-}
-
 static int cc26xx_write(struct flash_bank *bank, const uint8_t *buffer,
 	uint32_t offset, uint32_t count)
 {
@@ -508,11 +502,6 @@ static int cc26xx_auto_probe(struct flash_bank *bank)
 	return retval;
 }
 
-static int cc26xx_protect_check(struct flash_bank *bank)
-{
-	return ERROR_OK;
-}
-
 static int cc26xx_info(struct flash_bank *bank, char *buf, int buf_size)
 {
 	struct cc26xx_bank *cc26xx_bank = bank->driver_priv;
@@ -555,13 +544,11 @@ struct flash_driver cc26xx_flash = {
 	.name = "cc26xx",
 	.flash_bank_command = cc26xx_flash_bank_command,
 	.erase = cc26xx_erase,
-	.protect = cc26xx_protect,
 	.write = cc26xx_write,
 	.read = default_flash_read,
 	.probe = cc26xx_probe,
 	.auto_probe = cc26xx_auto_probe,
 	.erase_check = default_flash_blank_check,
-	.protect_check = cc26xx_protect_check,
 	.info = cc26xx_info,
 	.free_driver_priv = default_flash_free_driver_priv,
 };