config: remove unused GCC_VERSION_4_8 config symbols

Lets remove unused GCC_VERSION_4_8 symbol after the series of patches
which has switched to target gcc-8 by default.

Signed-off-by: Paul Spooren <[email protected]>
[refactored into separate commit]
Signed-off-by: Petr Štetiar <[email protected]>

config/Config-build.in

@@ -243,7 +243,6 @@ menu "Global build settings"
 		config PKG_CC_STACKPROTECTOR_STRONG
 			bool "Strong"
 			select GCC_LIBSSP if !USE_MUSL
-			depends on !GCC_VERSION_4_8
 			depends on KERNEL_CC_STACKPROTECTOR_STRONG
 	endchoice
 
@@ -258,7 +257,6 @@ menu "Global build settings"
 		config KERNEL_CC_STACKPROTECTOR_REGULAR
 			bool "Regular"
 		config KERNEL_CC_STACKPROTECTOR_STRONG
-			depends on !GCC_VERSION_4_8
 			bool "Strong"
 	endchoice