pinctrl: qcom: Update SPI config register offset calculation

SPI irq number needs to be used to calculate offset value
for spi config register. Update the calculation to use SPI
irq number instead of hwirq.

Change-Id: I94ba652523eb8ef2b73d09737950374f15d93467
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>