remoteproc/mediatek: Use size_t type for len in scp_da_to_va

remoteproc/mediatek: Use size_t type for len in scp_da_to_va

Clang errors:

drivers/remoteproc/mtk_scp.c:364:14: error: incompatible function
pointer types initializing 'void *(*)(struct rproc *, u64, size_t)' (aka
'void *(*)(struct rproc *, unsigned long long, unsigned int)') with an
expression of type 'void *(struct rproc *, u64, int)' (aka 'void
*(struct rproc *, unsigned long long, int)')
[-Werror,-Wincompatible-function-pointer-types]
        .da_to_va       = scp_da_to_va,
                          ^~~~~~~~~~~~
1 error generated.

Make the same change as commit 0fcbb369f052 ("remoteproc: Use size_t
type for len in da_to_va"), which was not updated for the acceptance of
commit 63c13d61eafe ("remoteproc/mediatek: add SCP support for mt8183").

Fixes: 0fcbb369f052 ("remoteproc: Use size_t type for len in da_to_va")
Link: https://github.com/ClangBuiltLinux/linux/issues/927
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20200310211514.32288-1-natechancellor@gmail.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>