mfd: pmic8058: Remove pm8058_hard_reset_config implementation

pm8xxx_hard_reset_config implements the required functionality,
replace the pm8058 specific call with this.

Remove ssbi_read/ssbi_write functions used in pm8058_hard_reset_config.
Remove unused variable(pm_lock) and enum(pon_config, pm8058_smpl_delay).

Change-Id: I3c5982ebab9277dc088bd3abd5621eb9acf3add9
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>