ACPI / APEI: Remove silent flag from ghes_read_estatus()

Subsequent patches will split up ghes_read_estatus(), at which
point passing around the 'silent' flag gets annoying. This is to
suppress prink() messages, which prior to commit 42a0bb3f
("printk/nmi: generic solution for safe printk in NMI"), were
unsafe in NMI context.

This is no longer necessary, remove the flag. printk() messages
are batched in a per-cpu buffer and printed via irq-work, or a call
back from panic().

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>