qemu-riscv: Remove obsolete CSR - send_ipi

This aligns the code in qemu-riscv with the code in spike-riscv.
The previous code gives an error in the updated toolchain as the
send_ipi CSR is no longer valid.

This gave the build error:
   Error: Instruction csrw requires absolute expression

Change-Id: Iac0f66e8e9935f45c8094d5e16bedb7ac5225424
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/16244
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
1 file changed