ARM: 6985/1: export functions to determine the presence of I/DTCM

By allowing code to detect whether DTCM or ITCM is present, code paths
involving TCM can be avoided when running on platforms that lack it.
This is good for creating single kernels across several archs, if some
of them utilize TCM but others don't.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>