package/ola: add missing python-numpy dependencies

Fixes:
WARNING: unmet direct dependencies detected for BR2_PACKAGE_PYTHON_NUMPY
  Depends on [n]: BR2_PACKAGE_PYTHON3 [=y] && BR2_PACKAGE_PYTHON_NUMPY_ARCH_SUPPORTS [=y] && (BR2_TOOLCHAIN_USES_GLIBC [=n] || BR2_TOOLCHAIN_USES_MUSL [=n])
  Selected by [y]:
  - BR2_PACKAGE_OLA_RDM_TESTS [=y] && BR2_PACKAGE_OLA [=y] && BR2_PACKAGE_OLA_PYTHON_BINDINGS [=y] && BR2_PACKAGE_PYTHON_NUMPY_ARCH_SUPPORTS [=y]

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>