boards/arm: disco_l475_iot1: case correction.

This commit changes from upper case to lower case in
"reg = <0x000D8000 DT_SIZE_M(7)"
"reg = <0x00000000 0x000D8000>"

Signed-off-by: Krishna Mohan Dani <krishnamohan.d@hcl.com>
1 file changed