clocksource: Make the int help prompt unit readable in ncurses

When doing

  make menuconfig

and searching for the CLOCKSOURCE_WATCHDOG_MAX_SKEW_US config item, the
help says:

  │ Symbol: CLOCKSOURCE_WATCHDOG_MAX_SKEW_US [=125]
  │ Type  : integer
  │ Range : [50 1000]
  │ Defined at kernel/time/Kconfig:204
  │   Prompt: Clocksource watchdog maximum allowable skew (in   s)
  							      ^^^

  │   Depends on: GENERIC_CLOCKEVENTS [=y] && CLOCKSOURCE_WATCHDOG [=y]

because on some terminals, it cannot display the 'μ' char, unicode
number 0x3bc.

So simply write it out so that there's no trouble.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240428102143.26764-1-bp@kernel.org

kernel/time/Kconfig

@@ -202,7 +202,7 @@ config HIGH_RES_TIMERS
 	  the size of the kernel image.
 
 config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
-	int "Clocksource watchdog maximum allowable skew (in μs)"
+	int "Clocksource watchdog maximum allowable skew (in microseconds)"
 	depends on CLOCKSOURCE_WATCHDOG
 	range 50 1000
 	default 125