ACPI / table: remove duplicate NULL check for the handler of acpi_table_parse()

In acpi_table_parse(), pointer of the table to pass to handler() is
checked before handler() called, so remove all the duplicate NULL
check in the handler function.

CC: Tony Luck <tony.luck@intel.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --cc arch/ia64/kernel/acpi.c
Simple merge

diff --cc arch/x86/kernel/acpi/boot.c
Simple merge

diff --cc drivers/acpi/numa.c
Simple merge