cfg: remove deprecated stm32 target configs

These were deprecated in commit 69ac20a1.

Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Change-Id: I047872f8cd61b42aaca6588ab75566219e4a3f5d
Reviewed-on: http://openocd.zylin.com/741


Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

tcl/target/stm32.cfg

-# deprecated cfg file
-echo "DEPRECATED! use script 'target/stm32f1x.cfg' not 'target/stm32.cfg'"
-source [find target/stm32f1x.cfg]

tcl/target/stm32f2xxx.cfg

-# deprecated cfg file
-echo "DEPRECATED! use script 'target/stm32f2x.cfg' not 'target/stm32f2xxx.cfg'"
-source [find target/stm32f2x.cfg]