mmc: sdhci-msm: Fix NULL pointer dereference

If during early boot register dump is called, then
there could be a NULL pointer dereference since mmc_host
structure might not be populated with cq_host info.
Thus fix this by using sdhci_host to get cq_host structure info
in sdhci_msm_cmdq_dump_debug_ram.

Change-Id: Ieaca7887001daabd4a6a0b05f7b0048dc11bbeee
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>