power: pm8921-charger: NULL check in 'external_power_changed' callback
power: pm8921-charger: NULL check in 'external_power_changed' callback

The power-supply framework internally calls power_supply_changed
after registering a power-supply type. This ends up calling
'external_power_changed' callback which unconditionally
accesses 'the_chip' pointer (which gets initialized later).
Fix this by adding a NULL check.

CRs-Fixed: 466083
Change-Id: I75a58ca5ab37e44454f139a2644ab316afe3c4b8
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