[stm32flash] Add 32bits version

Previous update has replaced the 32 bits (PE32) version
by a 64 bits one (PE32+).
To avoid any issue for user running on 32 bits OS,
use the 32 bits version per default.
The 64 bits version can be used and is named "stm32flash64.exe"

Those binaries are now stored in "stm32flash/" directory
in order to be aligned with other host OS structure.
Serial upload has been updated and cleaned.

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

win/serial_upload.bat

@@ -8,16 +8,4 @@ cd %~dp0
 rem: the two line below are needed to fix path issues with incorrect slashes before the bin file name
 set str=%4
 set str=%str:/=\%
-stm32flash.exe -g 0x8000000 -b 115200 -w %str% %1
-rem: C:\Python27\python.exe stm32loader.py -e -w -p %1 -g -b 115200  %str%
-
-rem: ------------- use STM's own uploader 
-rem: ---- Need to remove the COM bit from the comm port as the STM prog just wants the number
-set commport=%1
-set commportnum=%commport:COM=%
-rem: --- The maple board may nee the -i setting to be -i STM32_Med-density_128K or STM32_Med-density_64K
-rem: ---- 64 bit version
-rem: "%ProgramFiles(x86)%\STMicroelectronics\Software\Flash Loader Demonstrator\STMFlashLoader.exe"  -c --pn %commportnum% --br 230400  -i STM32_High-density_256K -e --all -d --fn %str% --a 0x8000000 -r --a 0x8000000 
-
-rem:  -- 32 bit version
-rem: "%ProgramFiles%\STMicroelectronics\Software\Flash Loader Demonstrator\STMFlashLoader.exe"  -c --pn %commportnum% --br 230400  -i STM32_Med-density_64K -e --all -d --fn %str% --a 0x8000000 -r --a 0x8000000 
+stm32flash\stm32flash.exe -g 0x8000000 -b 115200 -w %str% %1