Removed second division by `refdiv` #1241

Job	Run time
Verifiy build on MSRV	4m 41s
Build on-target-tests	50s
Build rp2040-hal's features	1m 29s
Build rp2040-hal's examples	1m 26s
Execute host-runable tests	2m 34s
Check rp2040-hal for unused dependencies	1m 35s
	12m 35s

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