linux-user/arm: Remove bogus SVC 0xf0002 handling

linux-user/arm: Remove bogus SVC 0xf0002 handling

We incorrectly treat SVC 0xf0002 as a cacheflush request (which is a
NOP for QEMU).  This is the wrong syscall number, because in the
svc-immediate OABI syscall numbers are all offset by the
ARM_SYSCALL_BASE value and so the correct insn is SVC 0x9f0002.
(This is handled further down in the code with the other Arm-specific
syscalls like NR_breakpoint.)

When this code was initially added in commit 6f1f31c069b20611 in
2004, ARM_NR_cacheflush was defined as (ARM_SYSCALL_BASE + 0xf0000 + 2)
so the value in the comparison took account of the extra 0x900000
offset. In commit fbb4a2e371f2fa7 in 2008, the ARM_SYSCALL_BASE
was removed from the definition of ARM_NR_cacheflush and handling
for this group of syscalls was added below the point where we subtract
ARM_SYSCALL_BASE from the SVC immediate value. However that commit
forgot to remove the now-obsolete earlier handling code.

Remove the spurious ARM_NR_cacheflush condition.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 20200420212206.12776-3-peter.maydell@linaro.org