media: av7110: don't do float point math

It sounds that earlier versions of GCC have troubles when
doing const math at compile time, if no typecast is used:

on i386:
	ERROR: modpost: "__floatunsidf" [drivers/media/pci/ttpci/dvb-ttpci.ko] undefined!
	ERROR: modpost: "__ltdf2" [drivers/media/pci/ttpci/dvb-ttpci.ko] undefined!

The warning was generated on gcc (SUSE Linux) 7.5.0.
Gcc 9.2 compiles it fine.

As an added bonus, it also fixes this objtool warning:

	drivers/media/pci/ttpci/av7110_v4l.c:163:11: error: SSE register return with SSE disabled

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>