drm/xe/oa/uapi: Make bit masks unsigned

drm/xe/oa/uapi: Make bit masks unsigned

When building with gcc-5:

    In function ‘decode_oa_format.isra.26’,
	inlined from ‘xe_oa_set_prop_oa_format’ at drivers/gpu/drm/xe/xe_oa.c:1664:6:
    ././include/linux/compiler_types.h:510:38: error: call to ‘__compiletime_assert_1336’ declared with attribute error: FIELD_GET: mask is not constant
    [...]
    ./include/linux/bitfield.h:155:3: note: in expansion of macro ‘__BF_FIELD_CHECK’
       __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \
       ^
    drivers/gpu/drm/xe/xe_oa.c:1573:18: note: in expansion of macro ‘FIELD_GET’
      u32 bc_report = FIELD_GET(DRM_XE_OA_FORMAT_MASK_BC_REPORT, fmt);
		      ^

Fixes: b6fd51c62119 ("drm/xe/oa/uapi: Define and parse OA stream properties")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240729092634.2227611-1-geert+renesas@glider.be
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>