defconfig: Disable RTL8152 config on sdxlemur

Disable RTL8152 config on sdxlemur as it is not supported on
this target and can lead to device crash when used.

Change-Id: I54eb388e98ae5a74aee3c726a95a32183849575d
Signed-off-by: Elson Roy Serrao <eserrao@codeaurora.org>