genirq: No need to mask non trigger mode flags before __irq_set_trigger()

Some callers of __irq_set_trigger() masks all flags except trigger mode
flags. This is unnecessary, ase __irq_set_trigger() already does this
before usage of flags.

[ tglx: Moved the flag mask and adjusted comment. Removed the hunk in
  	enable_percpu_irq() as it is required there ]

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Link: http://lkml.kernel.org/r/20160719095408.13778-1-kuleshovmail@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>