Make mx25l compatible with jedec,spi-nor as well

A lot of dts files define the SPI flashes supported by mx25l as
compatible with 'jedec,spi-nor', so we add this to the mx25l
compat_data.

Approved by: adrian (mentor)
Sponsored by: Smartcom - Bulgaria AD
Differential Revision: https://reviews.freebsd.org/D5962