linux_spi: Stop messing up the units of SPI speed

'speed' is stored in Hz, so rename the variable to 'speed_hz' to
clarify any potential confusion. Also, when printing the speed after
setting it with an ioctl, convert it to kHz to match the units given
in the message.

Corresponding to flashrom svn r1769.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
1 file changed