staging: r8192U_core: Do not use kernel-doc formatting for !kernel-doc headers

staging: r8192U_core: Do not use kernel-doc formatting for !kernel-doc headers

Fixes the following W=1 kernel build warning(s):

 drivers/staging/rtl8192u/r8192U_core.c:3714: warning: Function parameter or member 'dev' not described in 'UpdateRxPktTimeStamp8190'
 drivers/staging/rtl8192u/r8192U_core.c:3714: warning: Function parameter or member 'stats' not described in 'UpdateRxPktTimeStamp8190'
 drivers/staging/rtl8192u/r8192U_core.c:3714: warning: expecting prototype for Function(). Prototype was for UpdateRxPktTimeStamp8190() instead
 drivers/staging/rtl8192u/r8192U_core.c:4314: warning: Function parameter or member 'dev' not described in 'UpdateReceivedRateHistogramStatistics8190'
 drivers/staging/rtl8192u/r8192U_core.c:4314: warning: Function parameter or member 'stats' not described in 'UpdateReceivedRateHistogramStatistics8190'
 drivers/staging/rtl8192u/r8192U_core.c:4314: warning: expecting prototype for Function(). Prototype was for UpdateReceivedRateHistogramStatistics8190() instead

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrea Merello <andrea.merello@gmail.com>
Cc: Jerry chuang <wlanfae@realtek.com>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210414181129.1628598-5-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>