Make delay values unsigned

There is no reason for negative delays in our use cases:
 - We don't need it (to work around any quirks).
 - sleep() (POSIX) uses an unsigned argument.
 - usleep() (POSIX) uses an unsigned argument.
 - Sleep() (Windows) uses an unsigned argument.

Change all callees as well (without any complications).

Corresponding to flashrom svn r1782.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/programmer.h b/programmer.h
index d4d1f90..4f4cc02 100644
--- a/programmer.h
+++ b/programmer.h
@@ -120,7 +120,7 @@
 	void *(*map_flash_region) (const char *descr, uintptr_t phys_addr, size_t len);
 	void (*unmap_flash_region) (void *virt_addr, size_t len);
 
-	void (*delay) (int usecs);
+	void (*delay) (unsigned int usecs);
 };
 
 extern const struct programmer_entry programmer_table[];
@@ -248,10 +248,10 @@
 #endif
 
 /* udelay.c */
-void myusec_delay(int usecs);
+void myusec_delay(unsigned int usecs);
 void myusec_calibrate_delay(void);
-void internal_sleep(int usecs);
-void internal_delay(int usecs);
+void internal_sleep(unsigned int usecs);
+void internal_delay(unsigned int usecs);
 
 #if CONFIG_INTERNAL == 1
 /* board_enable.c */
@@ -655,7 +655,7 @@
 /* serprog.c */
 #if CONFIG_SERPROG == 1
 int serprog_init(void);
-void serprog_delay(int usecs);
+void serprog_delay(unsigned int usecs);
 #endif
 
 /* serial.c */