x86/sgx: Fix a W=1 build warning in function comment

Building the SGX code with W=1 generates below warning:

  arch/x86/kernel/cpu/sgx/main.c:741: warning: Function parameter or
  struct member 'low' not described in 'sgx_calc_section_metric'
  arch/x86/kernel/cpu/sgx/main.c:741: warning: Function parameter or
  struct member 'high' not described in 'sgx_calc_section_metric'
  ...

The function sgx_calc_section_metric() is a simple helper which is only
used in sgx/main.c.  There's no need to use kernel-doc style comment for
it.

Downgrade to a normal comment.

Signed-off-by: Kai Huang <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

Author: kaihuang

arch/x86/kernel/cpu/sgx/main.c

@@ -732,7 +732,7 @@ int arch_memory_failure(unsigned long pfn, int flags)
 	return 0;
 }
 
-/**
+/*
  * A section metric is concatenated in a way that @low bits 12-31 define the
  * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
  * metric.