lib: spinlock_debug: Prevent continuous spin dump logs on panic

Once a spinlock lockup is detected on a CPU, we invoke a Kernel Panic.
During the panic handling, we might see more instances of spinlock
lockup from other CPUs. This causes the dmesg to be cluttered and makes
it cumbersome to detect what exactly happened.
Call spin_bug instead of calling spin_dump directly.

Change-Id: I57857a991345a8dac3cd952463d05129145867a8
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>