helper/types: cast to uint32_t,uint16_t to avoid UB by shifting int too far

helper/types: cast to uint32_t,uint16_t to avoid UB by shifting int too far

Without this, we have some types promoted to `int` when they need to be
`unsigned int`.

Here's some ubsan output hitting this:

Unfortunately, what happens is that things get promoted to `int`, but
need to be `unsigned int`. Here's the ubsan output:

src/helper/types.h:126:65: runtime error: left shift of 255 by 24 places cannot be represented in type 'int'
    #0 0x55978a612060 in le_to_h_u32 src/helper/types.h:126
    #1 0x55978a61ff9e in stlink_usb_read_reg src/jtag/drivers/stlink_usb.c:1539
    #2 0x55978a8cfd45 in adapter_load_core_reg_u32 src/target/hla_target.c:67
    #3 0x55978a9f48e3 in armv7m_read_core_reg src/target/armv7m.c:236
    #4 0x55978a8d24fc in adapter_load_context src/target/hla_target.c:372
    #5 0x55978a8d261b in adapter_debug_entry src/target/hla_target.c:396
    #6 0x55978a8d3123 in adapter_poll src/target/hla_target.c:457
    #7 0x55978a528357 in target_poll src/target/target.c:535
    #8 0x55978a539fd4 in target_wait_state src/target/target.c:2914
    #9 0x55978a556e20 in jim_target_wait_state src/target/target.c:5256
    #10 0x55978a5cca62 in command_unknown src/helper/command.c:1030
    #11 0x55978aaed894 in JimInvokeCommand /home/cody/d/openocd-code/jimtcl/jim.c:10364

Change-Id: I24f6abfd26b6980100657397d69c84f2b80a005a
Signed-off-by: Cody P Schafer <openocd@codyps.com>
Reviewed-on: http://openocd.zylin.com/4455
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins
Reviewed-by: Christopher Head <chead@zaber.com>