drivers: firmware: psci: Use __pa_symbol for cpu_resume

If CONFIG_DEBUG_VIRTUAL=y, during s2ram:

    virt_to_phys used for non-linear address: ffffff80085db280 (cpu_resume+0x0/0x20)
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 1628 at arch/arm64/mm/physaddr.c:14 __virt_to_phys+0x28/0x60
    ...
    [<ffffff800809abb4>] __virt_to_phys+0x28/0x60
    [<ffffff80084a0c38>] psci_system_suspend+0x20/0x44
    [<ffffff8008095b28>] cpu_suspend+0x3c/0x68
    [<ffffff80084a0b48>] psci_system_suspend_enter+0x18/0x20
    [<ffffff80080ea3e0>] suspend_devices_and_enter+0x3f8/0x7e8
    [<ffffff80080ead14>] pm_suspend+0x544/0x5f4

Fixes: 1a08e3d9 ("drivers: firmware: psci: Use __pa_symbol for kernel symbol")
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Will Deacon <will.deacon@arm.com>