Platform/ARM/Morello: manually poll QSPI status bit after erase/write

This patch adds a function to poll Nor flash memory's status register
bit (WIP bit) to wait for an erase/write operation to complete.
The polling timeout is set to 1 second.

Signed-off-by: sahil <sahil@arm.com>
Change-Id: I058bf012e68c386f3ec055b95a3a70183582d59e