hexagon: time: include asm/delay.h for prototypes

Clang warns about missing prototypes that are declared in this header:

  arch/hexagon/kernel/time.c:209:6: warning: no previous prototype for function '__delay' [-Wmissing-prototypes]
    209 | void __delay(unsigned long cycles)
        |      ^
  arch/hexagon/kernel/time.c:209:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
    209 | void __delay(unsigned long cycles)
        | ^
        | static
  arch/hexagon/kernel/time.c:224:6: warning: no previous prototype for function '__udelay' [-Wmissing-prototypes]
    224 | void __udelay(unsigned long usecs)
        |      ^
  arch/hexagon/kernel/time.c:224:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
    224 | void __udelay(unsigned long usecs)
        | ^
        | static

Link: https://lkml.kernel.org/r/20231130-hexagon-missing-prototypes-v1-10-5c34714afe9e@kernel.orgSigned-off-by: Nathan Chancellor <nathan@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/hexagon/kernel/time.c

@@ -17,6 +17,7 @@
 #include <linux/of_irq.h>
 #include <linux/module.h>
 
+#include <asm/delay.h>
 #include <asm/hexagon_vm.h>
 #include <asm/time.h>