glsl: Fix absurd whitespace conventions in the parser.

glsl: Fix absurd whitespace conventions in the parser.

Historically, we indented grammar production rules with a single 8-space
tab, but code inside of blocks used Mesa's 3-space indents.

This meant when editing code, you had to use an 8-space tab for the
first level of indentation, and 3-spaces after that.  Unless you
specifically configure your editor to understand this, it will get the
indentation wrong on every single line you touch, which quickly devolves
into a colossal waste of time.

It's also inconsistent with every other file in the entire project.

This patch removes all tabs and moves to a consistent 3-space indent.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>