dt-bindings: qpnp-fg-gen4: Support multiple profile loading

Add support for multiple profile loading based on battery age
level. User can select a profile based on batt_age_level property
runtime. If a valid profile exists for the battery age level, it
will be loaded. By default, a profile with age level 0 will be
loaded if the feature is enabled.

Add a property "qcom,multi-profile-load" to support this.

Change-Id: Ifc0298445a15f05c47a3a6503fcb2e8c986b3c85
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>