Platform: PSoC64: S-IRQ: Add plat_test.c

Derived from Musca B1 platform.
Please see the description in the two commits:
  commit a9f8e9ec3fe6ab6969b95af31b0fc787d9959261
  commit d3c7766b4703c9eeb8e5271c42dae29d188ebfe0

Change-Id: I2d57c6c8d54e0633caa30153bc2346e17e1bbba0
Signed-off-by: Alamy Liu <alamy.liu@cypress.com>
2 files changed