msm: camera: csiphy: Fill interrupt size variable

As a part of interrupt status dump, it needs details for number
of register to be read. This change fill the interrupt size
variable to do the correct operation.

CRs-Fixed: 2729624
Change-Id: I9ee97e5a6c495062753fbd0ed44a178908c5109b
Signed-off-by: Jigarkumar Zala <jzala@codeaurora.org>