efi/bgrt: Enable ACPI BGRT handling on arm64

Now that the ACPI BGRT handling code has been made generic, we can
enable it for arm64.

Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com>
[ Updated commit log to reflect that BGRT is only enabled for arm64, and added
  missing 'return' statement to the dummy acpi_parse_bgrt() function. ]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-8-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/efi-bgrt.h b/include/linux/efi-bgrt.h
index 2fd3993..e6f624b 100644
--- a/include/linux/efi-bgrt.h
+++ b/include/linux/efi-bgrt.h
@@ -6,6 +6,7 @@
 #ifdef CONFIG_ACPI_BGRT
 
 void efi_bgrt_init(struct acpi_table_header *table);
+int __init acpi_parse_bgrt(struct acpi_table_header *table);
 
 /* The BGRT data itself; only valid if bgrt_image != NULL. */
 extern size_t bgrt_image_size;
@@ -14,6 +15,10 @@
 #else /* !CONFIG_ACPI_BGRT */
 
 static inline void efi_bgrt_init(struct acpi_table_header *table) {}
+static inline int __init acpi_parse_bgrt(struct acpi_table_header *table)
+{
+	return 0;
+}
 
 #endif /* !CONFIG_ACPI_BGRT */