Fix build breakage in ep93xx-core

Commit ede55aaa "arm: ep93xx: use
DEFINE_RES_* macros" introduced a build breakage in ep93xx due to a
typo. Fix it.

Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: Hartley Sweeten <hsweeten@visionengravers.com>