BACKPORT: FROMLIST: arch/mm: Export direct {un,}map functions

Firmware and hypervisor drivers can donate system heap memory to their
respective firmware/hypervisor entities. Those drivers should unmap the
pages from the kernel's logical map before doing so.

Export can_set_direct_map, set_direct_map_invalid_noflush, and
set_direct_map_default_noflush.

Bug: 338347082
Link: https://lore.kernel.org/all/20240222-gunyah-v17-19-1e9da6763d38@quicinc.com/


Change-Id: Ib94aa30156db3a6b9a755228ed7c20c910caaf65
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Sreenad Menon <quic_sreemeno@quicinc.com>