gpio: qpnp-pin: Modify the initcall level for qpnp-pin

Change the initcall level from module_init to subsys_initcall
to allow early registration of the driver.

CRs-Fixed: 888582
Change-Id: Ic50070f4d51a5d8ddeef40368d037f295175404e
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>