misc: add keystone ipc irq chip

The keystone ipc interrupt mechanism have 28 source id bits.
In this irq chip patch provides 28 ipc interrupts, which are
derived from source id bits.

Following is the source id bits to irq mapping

SrcID	Bit	IRQ		For TCI6614
SRCS0	4	base		512
SRCS1	5	base + 1	513
SRCS2	6	base + 2	514
SRCS3	7	base + 3	515
........
........
SRCS27	31	base + 27	539

Signed-off-by: Sajesh Kumar Saran <sajesh@ti.com>
3 files changed