stand: remove redundant declarations

These are picked out by the amd64-gcc6 build; time() is declared in <time.h>
and delay() is declared in <bootstrap.h>. These are the correct places for
these in stand/, so remove the duplicate declarations and make sure the
delay() consumer in libefi that depended on the extra delay() declaration
includes <bootstrap.h>.

MFC after:	1 week

stand/common/bootstrap.h

@@ -345,8 +345,6 @@ void	delay(int delay);
 
 void	dev_cleanup(void);
 
-time_t	time(time_t *tloc);
-
 #ifndef CTASSERT
 #define	CTASSERT(x)	_Static_assert(x, "compile-time assertion failed")
 #endif

stand/efi/include/efilib.h

@@ -113,7 +113,6 @@ EFI_STATUS efi_main(EFI_HANDLE Ximage, EFI_SYSTEM_TABLE* Xsystab);
 
 EFI_STATUS main(int argc, CHAR16 *argv[]);
 void efi_exit(EFI_STATUS status) __dead2;
-void delay(int usecs);
 
 /* EFI environment initialization. */
 void efi_init_environment(void);

stand/efi/libefi/efihttp.c

@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/in_systm.h>
 
 #include <stand.h>
+#include <bootstrap.h>
 #include <net.h>
 
 #include <efi.h>