include/linux/firmware.h: Check for FW_ACTION_HOTPLUG.

include/linux/firmware.h: Check for FW_ACTION_HOTPLUG.

The FW_ACTION_HOTPLUG and FW_ACTION_NOHOTPLUG macros, and the 'hotplug'
(later renamed 'uevent') parameter of request_firmware_nowait() were
added in vanilla kernel 2.6.14.  Update the include/linux/firmware.h
compatibility code to work with kernels prior to 2.6.14.  If
FW_ACTION_HOTPLUG is not defined, omit the uevent parameter and define
FW_ACTION_HOTPLUG and FW_ACTION_NOHOTPLUG.  The uevent parameter will be
ignored for these older kernels so FW_ACTION_NOHOTPLUG will behave just
like FW_ACTION_HOTPLUG for these older kernels.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>