drivers: irqchip: qcom: Fix SDM855 pin data

The SDM855 pin data expects a negative value at the end of the array to
mark end of array. Without a negative value, the index could go beyond
the length of the array causing undefined accesses.

Change-Id: Ib088c1248b5346f1b62e7a8021f81abdf99cb9ea
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>