sysreset: implement MAX9807 sysreset functions

MAX8907 PMIC has embedded poweroff function used by some device to initiane
device power off. Implement it as optional sysreset driver guarded by
kconfig option and system-power-controller device tree property.

Tested-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/drivers/sysreset/Makefile b/drivers/sysreset/Makefile
index ded91a4..f5c78b2 100644
--- a/drivers/sysreset/Makefile
+++ b/drivers/sysreset/Makefile
@@ -11,6 +11,7 @@
 obj-$(CONFIG_$(PHASE_)POWEROFF_GPIO) += poweroff_gpio.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_GPIO) += sysreset_gpio.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_MAX77663) += sysreset_max77663.o
+obj-$(CONFIG_$(PHASE_)SYSRESET_MAX8907) += sysreset_max8907.o
 obj-$(CONFIG_SYSRESET_MPC83XX) += sysreset_mpc83xx.o
 obj-$(CONFIG_SYSRESET_MICROBLAZE) += sysreset_microblaze.o
 obj-$(CONFIG_SYSRESET_OCTEON) += sysreset_octeon.o