hw/intc/ioapic: Replace legacy st_phys() -> address_space_st()

hw/intc/ioapic: Replace legacy st_phys() -> address_space_st()

Prefer the address_space_ld/st API over the legacy ld_phys()
because it allow checking for bus access fault. However the
IOAPIC datasheet (82093AA Order Number: 290566-001) doesn't
mention any fault occuring when the system bus (ISA bus) is
accessed. The ISA bus neither offer a way to signal recoverable
access faults. Therefore just inline the stl_le_phys() call,
not specifying any memory transaction attribute nor expecting
transation result, per the definition in
"system/memory_ldst_phys_endian.h.inc":

  42 static inline void ST_PHYS(l)(ARG1_DECL, hwaddr addr, uint32_t val)
  43 {
  44     ADDRESS_SPACE_ST(l)(ARG1, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
  45 }

No logical change intended.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20260204204103.46343-4-philmd@linaro.org>