Revision 228586 changed useless_type_conversion_p and added mode
changes for MEM:BLKmode inputs in store_expr_with_bounds, but it
missed store_bit_field.  This caused ada/rts/s-regpat.ads to fail
compilation on x86_64-linux-gnu.

for  gcc/ChangeLog

	PR middle-end/67912
	* expmed.c (store_bit_field_1): Adjust mode of BLKmode inputs.

From-SVN: r228774