arm64: Fix silly typo in comment

I was passing through and figuered I'd fix this up:

	featuer -> feature
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/cpufeature.h

@@ -262,7 +262,7 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
 /*
  * CPU feature detected at boot time based on system-wide value of a
  * feature. It is safe for a late CPU to have this feature even though
- * the system hasn't enabled it, although the featuer will not be used
+ * the system hasn't enabled it, although the feature will not be used
  * by Linux in this case. If the system has enabled this feature already,
  * then every late CPU must have it.
  */