[mbedtls] remove config workaround

[jwhui]

Fixes #10251

[size-report]

Size Report of OpenThread

Merging #10263 into main(63442f7).

name	branch	text	data	bss	total
ot-cli-ftd	main	467040	856	66364	534260
	#10263	467040	856	66364	534260
	+/-	0	0	0	0
ot-ncp-ftd	main	435900	760	61576	498236
	#10263	435900	760	61576	498236
	+/-	0	0	0	0
libopenthread-ftd.a	main	236166	95	40310	276571
	#10263	236166	95	40310	276571
	+/-	0	0	0	0
libopenthread-cli-ftd.a	main	57533	0	8075	65608
	#10263	57533	0	8075	65608
	+/-	0	0	0	0
libopenthread-ncp-ftd.a	main	31863	0	5916	37779
	#10263	31863	0	5916	37779
	+/-	0	0	0	0
ot-cli-mtd	main	364520	760	51220	416500
	#10263	364520	760	51220	416500
	+/-	0	0	0	0
ot-ncp-mtd	main	347060	760	46448	394268
	#10263	347060	760	46448	394268
	+/-	0	0	0	0
libopenthread-mtd.a	main	158165	0	25182	183347
	#10263	158165	0	25182	183347
	+/-	0	0	0	0
libopenthread-cli-mtd.a	main	39756	0	8059	47815
	#10263	39756	0	8059	47815
	+/-	0	0	0	0
libopenthread-ncp-mtd.a	main	24743	0	5916	30659
	#10263	24743	0	5916	30659
	+/-	0	0	0	0
ot-cli-ftd-br	main	550768	864	131204	682836
	#10263	550768	864	131204	682836
	+/-	0	0	0	0
libopenthread-ftd-br.a	main	324592	100	105126	429818
	#10263	324592	100	105126	429818
	+/-	0	0	0	0
libopenthread-cli-ftd-br.a	main	71320	0	8099	79419
	#10263	71320	0	8099	79419
	+/-	0	0	0	0
ot-rcp	main	62216	564	20604	83384
	#10263	62216	564	20604	83384
	+/-	0	0	0	0
libopenthread-rcp.a	main	9542	0	5052	14594
	#10263	9542	0	5052	14594
	+/-	0	0	0	0
libopenthread-radio.a	main	18870	0	214	19084
	#10263	18870	0	214	19084
	+/-	0	0	0	0

[gilles-peskine-arm]

It should be enough to remove the inclusion of *adjust* and check_config. Defining internal symbols can lead to an inconsistent configuration, same as including *adjust* at the wrong time.

[gilles-peskine-arm]

Looks good to me