i965: Add renderbuffer surface indexes to debug

i965: Add renderbuffer surface indexes to debug

This patch is optional in the series. It does make the output much cleaner, but
there is some risk.

Sample output (v3):
0x00007e80:      0x231d7000:  SURF000: 2D R8G8B8A8_UNORM  VALIGN4 HALIGN4 Y-tiled
0x00007e84:      0x05000000:  SURF000: MOCS: 0x5 Base MIP: 0.0 (0 mips) Surface QPitch: 0
0x00007e88:      0x009f009f:  SURF000: 160x160 [AUX_NONE]
0x00007e8c:      0x0000027f:  SURF000: 1 slices (depth), pitch: 640
0x00007e90:      0x00000000:  SURF000: min array element: 0, array extent 1, MULTISAMPLE_1
0x00007e94:      0x00000000:  SURF000: x,y offset: 0,0, min LOD: 0
0x00007e98:      0x00000000:  SURF000: AUX pitch: 0 qpitch: 0
0x00007e9c:      0x09770000:  SURF000: Clear color: R(0)G(0)B(0)A(0)
0x00007ea0:      0x00001000:  SURF000: 0x00001000
0x00007ea4:      0x00000000:  SURF000: 0x00000000
0x00007ea8:      0x00000000:  SURF000: 0x00000000
0x00007eac:      0x00000000:  SURF000: 0x00000000
0x00007e40:      0x234df000:  SURF001: 2D R11G11B10_FLOAT  VALIGN4 HALIGN16 Y-tiled
0x00007e44:      0x09000000:  SURF001: MOCS: 0x9 Base MIP: 0.0 (0 mips) Surface QPitch: 0
0x00007e48:      0x009f009f:  SURF001: 160x160 [AUX_CCS_D (Uncompressed, MULTISAMPLE_COUNT=1)]
0x00007e4c:      0x0000027f:  SURF001: 1 slices (depth), pitch: 640
0x00007e50:      0x00000000:  SURF001: min array element: 0, array extent 1, MULTISAMPLE_1
0x00007e54:      0x00000000:  SURF001: x,y offset: 0,0, min LOD: 0
0x00007e58:      0x00000001:  SURF001: AUX pitch: 0 qpitch: 0
0x00007e5c:      0x09770000:  SURF001: Clear color: R(0)G(0)B(0)A(0)
0x00007e60:      0x0002b000:  SURF001: 0x0002b000
0x00007e64:      0x00000000:  SURF001: 0x00000000
0x00007e68:      0x0002a000:  SURF001: 0x0002a000
0x00007e6c:      0x00000000:  SURF001: 0x00000000

v2: Rebased on Topi's recent series which changed around some of the gen8
surface setup code.

v3: Use ralloc_asprintf instead of asprintf to be more friendly to non-GNU
platforms.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>