power: pm8921-charger: Add error handling logic
power: pm8921-charger: Add error handling logic

Handle return errors at multiple locations and report them
appropriately. While at it, fix functions which can report
valid negative values.

CRs-Fixed: 389633
Change-Id: Ib3b8121d721d17bc9086decd94ee10239a2ec5f4
Signed-off-by: Anirudh Ghayal <6965a7b3a67807f737dfd71d68e54d27340a5c95@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas