sh: kprobes: Remove unneeded kprobe_opcode_t casts

There is no need to cast a kprobe_opcode_t pointer to a kprobe_opcode_t
pointer.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/fc22b990d869fc2005990159d8072ae2774b1396.1709326528.git.geert+renesas@glider.be


Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>