power: reset: msm: add support to select both dumps

With Minidump support enabled, user may need to request
to dump both fulldump as well as minidump for debug purpose.

Add support on dload_mode sysfs entry to select both dumps.
Enable both dumps with command:
	echo both > /sys/kernel/dload/dload_mode

Change-Id: I2f7c4c6e26dc236c75ab89490990c87b7139880b
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>