powerpc/booke: Spelling s/date/data/

Caching dates is never a good idea ;-)

Fixes: e7affb1d ("powerpc/cache: add cache flush operation for various e500")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Scott Wood <oss@buserror.net>

arch/powerpc/kernel/cpu_setup_fsl_booke.S

@@ -231,7 +231,7 @@ _GLOBAL(__setup_cpu_e5500)
 	blr
 #endif
 
-/* flush L1 date cache, it can apply to e500v2, e500mc and e5500 */
+/* flush L1 data cache, it can apply to e500v2, e500mc and e5500 */
 _GLOBAL(flush_dcache_L1)
 	mfmsr	r10
 	wrteei	0