mesa: rename format_(un)pack.c functions to match format names (pt. 3)

mesa: rename format_(un)pack.c functions to match format names (pt. 3)

sed commands:
s/LUMINANCE_FLOAT32\b/L_FLOAT32/g
s/LUMINANCE_FLOAT16\b/L_FLOAT16/g
s/LUMINANCE_ALPHA_FLOAT32\b/LA_FLOAT32/g
s/LUMINANCE_ALPHA_FLOAT16\b/LA_FLOAT16/g
s/ALPHA_FLOAT32\b/A_FLOAT32/g
s/ALPHA_FLOAT16\b/A_FLOAT16/g
s/XBGR32323232_FLOAT\b/RGBX_FLOAT32/g
s/RGB9_E5_FLOAT\b/R9G9B9E5_FLOAT/g
s/R11_G11_B10_FLOAT\b/R11G11B10_FLOAT/g
s/INTENSITY_FLOAT16\b/I_FLOAT16/g
s/INTENSITY_FLOAT32\b/I_FLOAT32/g

v2: removed a few redundant/no-op substitutions

Reviewed-by: Reviewed-by: Roland Scheidegger <sroland@vmware.com>