omap4: Fix build break when used with gcc-4.4.1 (2009-q3)

This patch adds  argument to smc calls as gcc-4.4.1 requires it
otherwise the build breaks with 2009-q3 toolchanin.

arch/arm/mach-omap2/omap-headsmp.S: Assembler messages:
arch/arm/mach-omap2/omap-headsmp.S:36: Error: missing expression -- `smc'
arch/arm/mach-omap2/omap-headsmp.S:55: Error: missing expression -- `smc'
arch/arm/mach-omap2/omap-headsmp.S:63: Error: missing expression -- `smc'
make[1]: *** [arch/arm/mach-omap2/omap-headsmp.o] Error 1

Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>