serial: msm_geni_serial: Add new UART IPC log file in DMA mode

This patch adds new IPC log file to dump IRQ registers to know
the interrupt status in dma mode. This will help in debugging
interrupt storm issues in dma mode.

Also increase the IPC log buffer size.

Change-Id: I33a32e8d237769808a9c7553c9c3e6d1024d9f50
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>