Make the sys_arch_protect() mutex be recursive.
Make the sys_arch_protect() mutex be recursive.

Fixes #9744

Appears to be a lwIP porting bug. Comments in our porting layer say:

    This function should support recursive calls from the same task or interrupt. In other words, sys_arch_protect() could be called while already protected.



kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,mbedmicro/mbed,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed