ARM: Show proper respect for Heinrich Hertz by using the correct unit for frequency

The SI unit of frequency is Hertz, named after Heinrich Hertz, and is
given the symbol "Hz" to denote this.  "hz" is not the unit of frequency,
and is in fact meaningless.

Fix arch/arm to correctly use "Hz", thereby acknowledging Heinrich Hertz'
contribution to the modern world.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-davinci/include/mach/da8xx.h

@@ -36,7 +36,7 @@ extern void __iomem *da8xx_syscfg1_base;
 
 /*
  * If the DA850/OMAP-L138/AM18x SoC on board is of a higher speed grade
- * (than the regular 300Mhz variant), the board code should set this up
+ * (than the regular 300MHz variant), the board code should set this up
  * with the supported speed before calling da850_register_cpufreq().
  */
 extern unsigned int da850_max_speed;