fg-memif: update IMA error handling and clear sequence

Based on the hardware documentation, update the IMA error
handling and clear sequence. In addition, check for DMA errors
and clear it before SRAM transactions begin. Also, check for IMA
hardware status to run the IMA clear sequence during ima_init and
not just based on IMA exception status alone. This is to help
with FG SRAM access to resume again properly in case of an error
encountered.

Change-Id: I583fa51599a1cbbd029cb45c075429730d2e071b
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>