Remove unused code in kernel_read_write (#1050)

These declarations either aren't used or aren't needed, as testBase.h
already declares them.

Some definitions got moved to test_common.h, as these are duplicated
across few files. There's further opportunity to improve code reuse
via test_common.h, but that's for future patch.

Signed-off-by: Radek Szymanski <radek.szymanski@arm.com>
13 files changed