arm64: acpi: Remove __init from acpi_psci_use_hvc() for use by SDEI

SDEI inherits the 'use hvc' bit that is also used by PSCI. PSCI does all
its initialisation early, SDEI does its late.

Remove the __init annotation from acpi_psci_use_hvc().

Signed-off-by: James Morse <james.morse@arm.com>

==
The function name is unchanged as this bit is named 'PSCI_USE_HVC'
in table 5-37 of ACPIv6.1.