Give wwan microservice access to the config partition

mmagent from the wwan microservice uses GetCipherCredentials to decrypt
username/password for a cellular network. Internally, this depends on
IsTpmEnabled() function, which determines the status of TPM by checking
for the presence/absence of /config/device.cert.pem and
/config/device.key.pem. This means that wwan container should have the
config partition mounted as well, otherwise IsTpmEnabled() may return
incorrect value and cause the decryption to fail.

Signed-off-by: Milan Lenco <milan@zededa.com>
(cherry picked from commit 2dcaf10)

pkg/wwan/build.yml

@@ -5,6 +5,7 @@ config:
  - /lib/modules:/lib/modules
  - /dev:/dev
  - /run:/run
+ - /config:/config
  - /:/hostfs
  - /persist:/persist:rshared,rbind
  net: host