target-arm: fix LDMIA bug on page boundary

target-arm: fix LDMIA bug on page boundary
target-arm: fix LDMIA bug on page boundary

When consecutive memory locations are on page boundary, a base register may be
loaded before page fault occurs. After page fault handling, it losts the memory
location information. To solve this problem, loading a base register has to put back.

Signed-off-by: Yuyeon Oh <yuyeon.oh@samsung.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>