soc: qcom: Add QMI client driver for MFSE service

Add QMI client driver for Modem File System External(MFSE)
service. The service provides limited file system commands that
an off-chip client can invoke, such as setting and getting the
current EFS sync timer value.
Once MFSE service is registered, use the following commands:
To get current timer value:
 cat /sys/class/mfse_qmi_clnt/sync_timer/value
To set current timer value:
 echo <time> > /sys/class/mfse_qmi_clnt/sync_timer/value.

Change-Id: I379c7050169f57e3bfaee6f6353ad1cbac6f5276
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>