drivers: qcom: ipc: Initialize PIL handle in error case

When loading either a non-modem image or when PIL returns an error,
the PIL handle is left uninitialized. This results in a kernel
panic when the handle is used to do a PIL unload.

Initialize the pil handle in this error case to avoid kernel panic.

CRs-Fixed: 636748
Change-Id: I83fb2ff822851e0b5a35cb32b440671b46068d85
Signed-off-by: Steven Cahail <scahail@codeaurora.org>