arch/Config.in.arm: Use armv6k for arm1136jf-s rev1

According to the ARM1136JF-S and ARM1136J-S Revision r1p5 Technical Reference
Manual, from release rev1 (r1pn), the ARM1136JF-S processor implements the ARMv6
instruction set with the ARMv6k additions.

This patch differentiates the ARM1136JF-S revisions 0 and 1 in order to use
either ARMv6j (e.g. on Freescale i.MX31) or ARMv6k (e.g. on Freescale i.MX35).

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>