arch: arm: aarch32: initialize FPSCR to reset value for ARMv8.1

With GCC 11 now supporting low overhead branching in ARMv8.1, ASM "LE"
(loop-end) instructions would trigger an INVSTATE hard-fault after
FPSCR was set to 0. This was due to the FPSCR getting a new field in
ARMv8.1. LTPSIZE is now set to it's reset value of Tail predication not
applied.

Signed-off-by: Ryan McClelland <ryanmcclelland@fb.com>