ARM: spear: make spear3xx/6xx mach/spear.h files identical

The two files are almost identical already basically just differ
in the identifier names. By changing the identifiers to be the
same, we are able to merge the two as a preparation to building
a combined kernel.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>