[prim_generic] Factor out loading for 1p RAM
[prim_generic] Factor out loading for 1p RAM

Similar to 2297a614743c346df4ab5efa90a9347f0475d99a, which should have
included this change as part of the refactoring.

Signed-off-by: Philipp Wagner <5a4b10454c30419e54a1570be358a516ff84bb63@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan