package/mesa3d: fix musl related compile failures

package/mesa3d: fix musl related compile failures

Fixes:

  http://autobuild.buildroot.net/results/1881daae69992e30a9c1fff1f639d57f82e6ee19

  ../src/gallium/drivers/vc4/vc4_bufmgr.c:110:57: error: format '%ld' expects argument of type 'long int', but argument 3 has type 'time_t' {aka 'long long int'} [-Werror=format=]

  ../src/gallium/drivers/panfrost/pan_bo.h:93:9: error: unknown type name ‘time_t’

  ../src/gallium/drivers/v3d/v3d_bufmgr.c:83:57: error: format ‘%ld’ expects argument of type ‘long int’, but argument 3 has type ‘time_t’ {aka ‘long long int’} [-Werror=format=]

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>