gallium/tgsi: correct typo propagated from NV_vertex_program1_1

gallium/tgsi: correct typo propagated from NV_vertex_program1_1

In the specification text of NV_vertex_program1_1, the upper
limit of the RCC instruction is written as 1.884467e+19 in
scientific notation, but as 0x5F800000 in binary. But the binary
version translates to 1.84467e+19 rather than 1.884467e+19 in
scientific notation.

Since the lower-limit equals 2^-64 and the binary version equals
2^+64, let's assume the value in scientific notation is a typo
and implement this using the value from the binary version
instead.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>