cpu/intel: Fix the remaining issues detected by checkpatch

Fix the following error and warnings detected by checkpatch.pl:

ERROR: switch and case should be at the same indent
WARNING: Consecutive strings are generally better as a single string
WARNING: static const char * array should probably be static const char * const

TEST=Build and run on Galileo Gen2

Change-Id: I03d5d0d2db0d5e9b33c8ec807b236fe229bcc8f3
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/18851
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/intel/turbo/turbo.c

@@ -42,7 +42,7 @@ static inline void set_global_turbo_state(int state)
 }
 #endif
 
-static const char *turbo_state_desc[] = {
+static const char * const turbo_state_desc[] = {
 	[TURBO_UNKNOWN]		= "unknown",
 	[TURBO_UNAVAILABLE]	= "unavailable",
 	[TURBO_DISABLED]	= "available but hidden",