mfd: cgbc-core: Cleanup signedness in cgbc_session_request()

This doesn't affect how the code works because there are some implicit
casts, but the "ret" variable is used to hold negative error codes so
it should be type int.

Declare it as "int" instead of "unsigned int".

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/9e812dfa-e216-4e40-bbf0-d0b63b110bb0@stanley.mountain
Signed-off-by: Lee Jones <lee@kernel.org>

Author: Dan Carpenter

drivers/mfd/cgbc-core.c

@@ -96,7 +96,7 @@ static int cgbc_session_command(struct cgbc_device_data *cgbc, u8 cmd)
 
 static int cgbc_session_request(struct cgbc_device_data *cgbc)
 {
-	unsigned int ret;
+	int ret;
 
 	ret = cgbc_wait_device(cgbc);