QSPI Flash Driver Never Returns

[xmos-jmccarthy]

System information
All versions as of 05712a4

Describe the current behavior
Using the qspi_flash driver to read an address outside of the bounds of flash results in an infinite loop that never returns, essentially locking use of qspi flash driver.

Describe the expected behavior
The driver should return when reading past flash address space.

Standalone code to reproduce the issue
Read any address outside of flash.