flash: use proper format with uint32_t

flash: use proper format with uint32_t

Modify the format strings to properly handle uint32_t data types.

Change the type of variable retval in 'nor/ambiqmicro.c' to match
both the value to carry and the returned type of the function.

Fix the prototype mismatch of function lpc2900_address2sector()
between the header and the C file.

Change-Id: I68ffba9bd83eec8132f83bff3af993861fd09d84
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5816
Tested-by: jenkins