configs/qemu: Update defconfigs to Linux 4.19.16

Linux version are changed to 4.19.16 (LTS) for all qemu defconfigs,
except for riscv. riscv defconfigs are left unchanged because they have
a custom Linux repository causing more difficulties when upgrading to
4.19 for riscv32. And for the riscv64, it has been updated recently to
Linux 4.20 by another contributor.

Patch for arm-versatile-nommu is changed into a git format

Add cache attributes for xtensa-lx60-nommu config because the commit
https://github.com/torvalds/linux/commit/7bb516ca5424e12b42124fab2906b6da9c81ba9c


added a new config variable for memory cache attribute:
CONFIG_MEMMAP_CACHEATTR

All these updated configs have been built successfully.

Signed-off-by: Gerome Burlats <gerome.burlats@smile.fr>
Cc: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>