spi_qsd: shrink the probe function

Shrink the probe function to avoid the dependency of
the hardware interaction like clocks and bam. This avoids
the system boot-up delay due to hardware depndency.

Change-Id: I4c92428eda4f4da653a05f3c8f0a8941aa621bec
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>