[ACPI] acpi_register_gsi() can return error

Current acpi_register_gsi() function has no way to indicate errors to its
callers even though acpi_register_gsi() can fail to register gsi because of
some reasons (out of memory, lack of interrupt vectors, incorrect BIOS, and so
on).  As a result, caller of acpi_register_gsi() cannot handle the case that
acpi_register_gsi() fails.  I think failure of acpi_register_gsi() should be
handled properly.

This series of patches changes acpi_register_gsi() to return negative value on
error, and also changes callers of acpi_register_gsi() to handle failure of
acpi_register_gsi().

This patch changes the type of return value of acpi_register_gsi() from
"unsigned int" to "int" to indicate an error.  If acpi_register_gsi() fails to
register gsi, it returns negative value.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index ca0cd24..9378bcd 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -432,7 +432,7 @@
 
 #endif 	/*!CONFIG_ACPI_BOOT*/
 
-unsigned int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low);
+int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low);
 int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
 
 /*