src/main: fix format argument for printing gsize in status formatters
src/main: fix format argument for printing gsize in status formatters

gsize should be printed with type G_GSIZE_FORMAT to prevent build warnings:

| src/main.c: In function 'r_status_formatter_readable':
| src/main.c:972:34: warning: format '%lu' expects argument of type 'long unsigned int', but argument 3 has type 'gsize {aka unsigned int}' [-Wformat=]
|      g_string_append_printf(text, "\n              size=%lu", slot_state->checksum.size);
|                                   ^
| src/main.c: In function 'r_status_formatter_shell':
| src/main.c:1067:26: warning: format '%lu' expects argument of type 'long unsigned int', but argument 2 has type 'gsize {aka unsigned int}' [-Wformat=]
|     str = g_strdup_printf("%lu", slot_state->checksum.size);
|                           ^

Signed-off-by: Enrico Joerns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

ejoerns/rauc,rauc/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc,jluebbe/rauc,rauc/rauc,rauc/rauc,ejoerns/rauc