tcl/target/stm32g4x: drop useless reset-start event

There is no boost of adapter speed in reset-init event
so it's not necessary to set back the safe speed in reset-start

Change-Id: I8b78442471390f7183c39d67b29788cccc98d018
Signed-off-by: Tomas Vanek <[email protected]>
Reviewed-on: https://review.openocd.org/c/openocd/+/9128
Tested-by: jenkins
Reviewed-by: Antonio Borneo <[email protected]>
Reviewed-by: zapb <[email protected]>
Reviewed-by: Ahmed Haoues <[email protected]>

Author: tom-van

tcl/target/stm32g4x.cfg

@@ -83,11 +83,6 @@ $_TARGETNAME configure -event reset-init {
 	mmw 0x40021008 0x00000001 0x00000002	;# RCC_CFGR: SW=HSI16
 }
 
-$_TARGETNAME configure -event reset-start {
-	# Reset clock is HSI (16 MHz)
-	adapter speed 2000
-}
-
 $_TARGETNAME configure -event examine-end {
 	# DBGMCU_CR |= DBG_STANDBY | DBG_STOP | DBG_SLEEP
 	mmw 0xE0042004 0x00000007 0