msm: qti_sdio_client: Return error number in diag callback

Return error number in the diag callback to handle it in calback's
error handling sequence. This potentially fixes a memory leak when
device is reenumerated multiple times such as during SSR.

Change-Id: I841d07dfa2f3231e54c5145f27dda977fa8c9f97
Signed-off-by: Amandeep Singh <amansing@codeaurora.org>