openpower: mmc: physical reset triggers bios reset

The service openpower-bios-factory-reset runs during startup and
calls bios_reset_check. This method determines whether the
factory-reset-toggle gpio has changed since the last reboot and
triggers a bios reset if it has. This decouples the code to check
for bios resets from the code in item_updater_mmc::reset and from
the BMC factory reset code.

Tested: Verified that the reset-gpio-val file was created to store
the previous value of the environment variable rwreset. Added files
to /media/hostfw and verified that they were removed upon reboot
when the value in reset-gpio-val differed from rwreset.

Signed-off-by: Isaac Kurth <isaac.kurth@ibm.com>
Change-Id: I9942c1826f800a2ce9aef4b9456b3f4acc4b94fe
diff --git a/meson.build b/meson.build
index 33869a9..2c0d3c4 100644
--- a/meson.build
+++ b/meson.build
@@ -126,6 +126,7 @@
     extra_unit_files += [
         'mmc/obmc-flash-bios-init.service',
         'mmc/obmc-flash-bios-patch.service',
+        'mmc/openpower-bios-factory-reset.service',
     ]
 endif