Fix spelling of ARM Cortex

It's Cortex-Xn, not Cortex Xn or cortex xn or cortex-xn or CORTEX-Xn
or CortexXn. Further it's Cortex-M0+, not M0plus.

Cf. http://www.arm.com/products/processors/index.php

Consistently write it the official way, so that it stops propagating.
Originally spotted in the documentation, it mainly affects code comments
but also Atmel SAM3/SAM4/SAMV, NiietCM4 and SiM3x flash driver output.

Found via:

  git grep -i "Cortex "
  git grep -i "Cortex-" | grep -v "Cortex-" | grep -v ".cpu"
  git grep -i "CortexM"

Change-Id: Ic7b6ca85253e027f6f0f751c628d1a2a391fe914
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-on: http://openocd.zylin.com/3483
Tested-by: jenkins
Reviewed-by: Marc Schink <openocd-dev@marcschink.de>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

src/target/cortex_m.c

@@ -1932,7 +1932,7 @@ int cortex_m_examine(struct target *target)
 		}
 		LOG_DEBUG("cpuid: 0x%8.8" PRIx32 "", cpuid);
 
-		/* test for floating point feature on cortex-m4 */
+		/* test for floating point feature on Cortex-M4 */
 		if (i == 4) {
 			target_read_u32(target, MVFR0, &mvfr0);
 			target_read_u32(target, MVFR1, &mvfr1);